Essential Neonatal Medicine E-Book

Sunil Sinha

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Serie: essentials
• Sprache: Englisch

Seitenzahl: 875

Veröffentlichungsjahr: 2017

Beschreibung

Providing a comprehensive yet concise guide for trainee doctors, neonatal nurses and midwives, Essential Neonatal Medicine continues to be an indispensable resource that combines the depth and breadth of a textbook with the efficiency of a revision guide.

Extensively updated and full-colour throughout, this edition includes new chapters on neonatal transport and palliative care, as well as further content on pathophysiology and embryology, quality improvement and risk management, infection control, and non-invasive ventilation.

With an improved artwork programme and a new glossary of terms, Essential Neonatal Medicine is ideal for all trainee health professionals new to neonatology, or looking for a comprehensive aid to support them.

Leseprobe

This title is also available as an e-book.

For more details, please see

www.wiley.com/buy/9781119235811

Essential Neonatal Medicine

Sixth Edition

Sunil Sinha

Professor of Paediatrics University of Durham Consultant Neonatologist James Cook University Hospital Middlesbrough, UK

Lawrence Miall

Consultant Neonatologist, Leeds Children's HospitalHonorary Senior Lecturer, University of Leeds Leeds Teaching Hospitals NHS Trust Leeds, UK

Luke Jardine

Senior Staff Specialist Neonatology, Mater Mothers' Hospital Honorary Researcher, Mater Research Associate Professor, The University of Queensland Australia

This edition first published 2018 © 2018 John Wiley & Sons Ltd

Edition HistoryJohn Wiley & Sons (1e 1987; 2e 1993; 3e 2000); Wiley-Blackwell (4e 2008; 5e 2012).

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording or otherwise, except as permitted by law. Advice on how to obtain permission to reuse material from this title is available at http://www.wiley.com/go/permissions.

The right of Sunil Sinha, Lawrence Miall, Luke Jardine to be identified as the authors of this work has been asserted in accordance with law.

Registered Office(s)John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, USA John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK

Editorial Office9600 Garsington Road, Oxford, OX4 2DQ, UK

For details of our global editorial offices, customer services, and more information about Wiley products visit us at www.wiley.com.

Wiley also publishes its books in a variety of electronic formats and by print-on-demand. Some content that appears in standard print versions of this book may not be available in other formats.

Limit of Liability/Disclaimer of WarrantyThe contents of this work are intended to further general scientific research, understanding, and discussion only and are not intended and should not be relied upon as recommending or promoting scientific method, diagnosis, or treatment by physicians for any particular patient. The publisher and the authors make no representations or warranties with respect to the accuracy and completeness of the contents of this work and specifically disclaim all warranties, including without limitation any implied warranties of fitness for a particular purpose. In view of ongoing research, equipment modifications, changes in governmental regulations, and the constant flow of information relating to the use of medicines, equipment, and devices, the reader is urged to review and evaluate the information provided in the package insert or instructions for each medicine, equipment, or device for, among other things, any changes in the instructions or indication of usage and for added warnings and precautions. Readers should consult with a specialist where appropriate. The fact that an organization or website is referred to in this work as a citation and/or potential source of further information does not mean that the author or the publisher endorses the information the organization or website may provide or recommendations it may make. Further, readers should be aware that websites listed in this work may have changed or disappeared between when this works was written and when it is read. No warranty may be created or extended by any promotional statements for this work. Neither the publisher nor the author shall be liable for any damages arising herefrom.

Library of Congress Cataloging-in-Publication DataNames: Sinha, Sunil K., M.D., Ph.D., author. | Miall, Lawrence, author. | Jardine, Luke, author. Title: Essential neonatal medicine / Sunil Sinha, Lawrence Miall, Luke Jardine. Other titles: Essentials (Wiley-Blackwell (Firm)) Description: Sixth edition. | Hoboken, NJ : John Wiley & Sons Inc., 2018. |     Series: Essentials | Includes bibliographical references and index. Identifiers: LCCN 2017007280 (print) | LCCN 2017008052 (ebook) | ISBN     9781119235811 (paper) | ISBN 9781119235774 (Adobe PDF) | ISBN     9781119235750 (ePub) Subjects: | MESH: Infant, Newborn, Diseases | Neonatology | Infant, Newborn Classification: LCC RJ251 (print) | LCC RJ251 (ebook) | NLM WS 421 | DDC     618.92/01—dc23 LC record available at https://lccn.loc.gov/2017007280

Cover Design: Wiley Cover Image: © ERproductions Ltd/Gettyimages

CONTENTS

Preface to the Sixth Edition

Acknowledgements

Preface to the First Edition

Abbreviations

How to use your textbook

About the companion website

Chapter 1 The fetus, placenta and changes at birth

Introduction

Placental function

Fetal homeostasis

Fetal circulation

Assessment of fetal well-being

Screening during pregnancy

Fetal monitoring during labour

Fetal compromise

Acknowledgements

Further reading

Chapter 2 Perinatal epidemiology and audit

Introduction

Definitions of terms commonly used in perinatal medicine

The role of perinatal and neonatal audit

Classification of perinatal deaths

Factors affecting perinatal death rates

Prevention of perinatal mortality and 
low birthweight

Changing trends

Further reading

Chapter 3 Multiple births

Introduction

Physiology of fertilization, implantation and placenta formation

Classification of multiple pregnancy

Assisted reproductive technology

Incidence of multiple pregnancies

Parental counselling

Complications of multiple pregnancy

Further reading

Chapter 4 Neonatal consequences of maternal conditions

Introduction

Congenital anomalies: malformations and deformations

Congenital anomalies associated with teratogens

Congenital malformation secondary to maternal infections

Consequences of maternal substance misuse

Neonatal manifestations of maternal medical diseases

Further reading

Chapter 5 Resuscitation at birth

Introduction

Fetal responses during labour

Fetal and neonatal responses to perinatal asphyxia

Perinatal asphyxia

Assessment of the infant at birth

Stabilization at birth

Resuscitation

Post-resuscitation care of the 
asphyxiated infant

Further reading

Chapter 6 Examination of the newborn

Introduction

The newborn examination as a 
screening test

Approach to the newborn examination

General appearance

Head and neck

Chest

Cardiovascular

Abdomen

Back

Extremities

Congenital abnormalities of the hips 
and limbs

Skin disorders

Communication with parents

Further reading

Chapter 7 Birth injury

Introduction

Risk factors for birth injury

Injuries to the scalp, skull and brain

Bone and joint injuries

Peripheral nerve injuries

Soft-tissue injuries

Organ injuries

Injuries sustained in the neonatal intensive care unit (NICU)

Further reading

Chapter 8 Genetic disorders

Introduction

Gene structure

Commonly used investigations

Genetic variation

Multifactorial inheritance

Approach to the dysmorphic neonate

Prevention of congenital abnormalities

Further reading

Chapter 9 Infant feeding and nutrition

Introduction

Specific nutritional requirements

Breastfeeding

Artificial feeding/formulas

Techniques of artificial feeding

Feeding the preterm infant

Parenteral nutrition

Common feeding disorders

Further reading

Chapter 10 Infection in the newborn

Introduction

The immune system

Susceptibility of the neonate to infection

Congenital infection

Intrapartum (early-onset) infection

Postnatal (late-onset) infection

Further reading

Chapter 11 The extreme preterm infant

Introduction

Gestational age

Causes and management of preterm labour

Survival and outcome for the preterm infant

Preterm delivery at the margins of viability

Stabilization at birth and management in the ‘golden hour’

Common problems to be expected in the preterm infant

Supportive care on the NICU

Preparation for discharge home

Further reading

Chapter 12 The low-birthweight infant

Introduction

The infant who is small for gestational age

Causes of intrauterine growth restriction

Problems to be expected in the growth-restricted fetus and 
SGA infant

Management of the low-birthweight infant

Further reading

Chapter 13 Respiratory physiology and respiratory support

Introduction

Fetal lung development

Pulmonary surfactants

Respiratory physiology

Assessment of respiratory function

Respiratory failure

Mechanical ventilation

Further reading

Chapter 14 Respiratory disorders

Introduction

Respiratory distress

Transient tachypnoea of the newborn

Respiratory distress syndrome (RDS)

Pneumonia

Pulmonary air leaks

Meconium aspiration syndrome

Pulmonary hypoplasia

Pulmonary haemorrhage

Congenital diaphragmatic hernia

Oesophageal atresia and 
tracheo-oesophageal fistula

Congenital lobar emphysema

Congenital pulmonary airway malformation (CPAM) [formerly known as congenital cystic adenomatous malformation; CCAM]

Chronic lung disease and bronchopulmonary dysplasia (BPD)

Further reading

Chapter 15 Apnoea, bradycardia and upper airway obstruction

Introduction

Physiology

Apnoea

Acute life-threatening events (ALTEs)

Sudden and unexpected infant death and sudden infant death syndrome

Upper airway obstruction

Further reading

Chapter 16 Cardiovascular disorders

Introduction

Physiology of the cardiovascular system

Blood pressure

Hypertension

Congenital heart disease

Investigations

Cyanotic heart disease

Congestive heart failure

Left-to-right shunts

Obstructive lesions

Dysrrhythmias

Circulatory maladaptation at birth

Further reading

Chapter 17 Gastrointestinal and abdominal disorders

Introduction

Development of the gastrointestinal tract

Malformations

Abdominal wall defects

Necrotizing enterocolitis

Short bowel syndrome

Rectal bleeding

Hernia

Hydrocoele

Undescended testis

Hypospadias

Further reading

Chapter 18 Renal disorders

Introduction

Role of amniotic fluid

Renal physiology

Normal urine output

Investigation of renal disease

Presentation of renal disease

Acute kidney injury

Urinary tract infection

Renal masses

Cystic disease of the kidneys

Haematuria

Ectopia vesicae (bladder exstrophy)

Further reading

Chapter 19 Jaundice

Introduction

Physiology of bilirubin metabolism

Clinical assessment of the jaundiced infant

Unconjugated hyperbilirubinaemia

Conjugated hyperbilirubinaemia

Further reading

Chapter 20 Haematological disorders

Introduction

Placental transfusion

Anaemia

Hydrops fetalis

Aplasia

Polycythaemia

Bleeding and coagulation disorders

Thrombocytopenia

Haemorrhagic disease of the newborn (Vitamin K-deficient bleeding)

Disseminated intravascular coagulation (DIC)

Inherited disorders of coagulation

Congenital deficiency of anticoagulant proteins (hypercoagulable states)

Further reading

Chapter 21 Endocrine and metabolic disorders

Introduction

Glucose homeostasis and its abnormalities

Disorders of calcium, phosphate and magnesium metabolism

Disorders of magnesium metabolism

Disorders of sodium and potassium metabolism

21.6.1 Box 21.3 Causes of neonatal hyponatraemia.

Endocrine gland disorders

Abnormalities of the adrenal gland

Inborn errors of metabolism

Further reading

Chapter 22 The central nervous system

Introduction

Brain development

Malformations of the central nervous system

Disorders of head size and shape

Intracranial haemorrhage (ICH)

Periventricular leukomalacia

Neonatal stroke

Hypoxic–ischaemic encephalopathy

Neonatal convulsions

Neonatal hypotonia (‘floppy infant’)

Further reading

Chapter 23 Neurodevelopmental follow-up and assessment of hearing and vision

Introduction

Neurodevelopmental outcome

Hearing impairment (deafness)

Visual impairment

Further reading

Chapter 24 Developmental care and the neonatal environment

Introduction

Thermoregulation

Skin care on the neonatal intensive care unit

Optimizing the neonatal environment

Procedural pain and analgesia

Developmental care

Further reading

Chapter 25 Organization of perinatal services

Introduction

Organization of perinatal services

Levels of perinatal care

Neonatal networks

Further reading

Chapter 26 Neonatal transport

Introduction

Transport

in utero

Preparation for transport

Transport equipment

The role of a neonatal transport service

Further reading

Chapter 27 Discharge and follow-up of high-risk infants

Introduction

Discharge of high-risk infants

Immunization

Specialized follow-up clinics

Follow-up of preterm infants

Further reading

Chapter 28 Parent–infant attachment and support for parents of critically ill infants

Introduction

Parent–infant attachment (bonding)

Care of parents of critically ill infants

Family integrated care

Further reading

Chapter 29 Ethical issues and decision-making process in the treatment of critically ill newborn infants

Introduction

Principles of ethical reasoning

Decision-making processes

The role of the Institutional 
Ethics Committee

Withholding and withdrawing 
life-sustaining treatment

Common neonatal ethical dilemmas

Parents in the decision-making process

Further reading

Chapter 30 End-of-life care and palliative care

Introduction – why babies die

Unexpected deaths (including sudden unexpected postnatal collapse)

What is palliative care?

Expected deaths and care planning

Making a care plan

Place of death: hospice versus home versus hospital

Symptom control

Organ donation

Autopsy

Caring for parents – grief and bereavement

Caring for staff

Further reading

Index

EULA

List of Illustrations

Chapter 1

Figure 1.1

Diagram of placental structures showing blood perfusion.

Figure 1.2

Diagram of the fetal circulation through the heart and lungs, showing the direction of flow through the foramen ovale and ductus arteriosus.

Figure 1.3

A timeline for fetal assessment and monitoring during pregnancy.

Figure 1.4

Doppler measurement of blood flow in the fetal umbilical artery. The left-hand panel shows normal forward flow throughout the cardiac cycle. The right-hand panel shows pathological reversed flow during diastole (see arrow).

Figure 1.5

Cleft lip. Illustration courtesy of Dr Jason Ong.

Figure 1.6

Fetal MRI scan (coronal view) showing large cystic hygroma on the left side of the neck (arrow) and an associated pleural effusion (arrow). Illustration courtesy of Dr Mike Weston.

Figure 1.7a

CTG showing fetal heart rate accelerations.

Figure 1.7b

CTG showing late decelerations.

Figure 1.7c

CTG showing normal heart rate followed by severe prolonged fetal bradycardia.

Figure 1.7d

CTG showing loss of beat-to-beat variability.

Figure 1.8

Clearance of lung fluid into the lymphatics with the first breaths.

Chapter 2

Figure 2.1

2014 ANZNN survival data to discharge home (with 95% CI) (Full data are available in Table 30 in Chow, S.S.W., Le Marsney, R., Haslam, R., Lui, K. (2016) Report of the Australian and New Zealand Neonatal Network 2014. ANZNN, Sydney.

Chapter 3

Figure 3.1

Twin peak or lambda sign. Illustration courtesy of Dr Scott Peterson, Mater Mothers’ Hospital. Reproduced with permission of Dr Peterson.

Chapter 4

Figure 4.1

Problems leading to joint contractures.

Figure 4.2

Infant with typical features of fetal alcohol syndrome. From Lissauer, T. and Fanaroff, A. A. (2011)

Neonatology at a Glance

, 2nd edition. © 2011, Blackwell Publishing Ltd. Reproduced with permission of John Wiley & Sons.

Chapter 5

Figure 5.1

The physiological effect of acute asphyxia and the response to resuscitation. Illustration courtesy of Dr Sam Richmond.

Figure 5.2

Algorithm for resuscitation. Reproduced with permission from the Resuscitation Council UK (2015).

Figure 5.3

Mask inflation with the head in the neutral position.

Figure 5.4

(a) T-piece (Fischer Pykell Health Care). (b) Face masks designed for use in face mask ventilation of term and preterm newborns.

Figure 5.5

Laryngoscopy. The laryngoscope blade displaces the tongue and lifts the epiglottis anteriorly to expose the cords 
(Source: Baillière Tindall).

Figure 5.6

The stages of intubation. (a) Visualization of the uvula and oropharynx. (b) The epiglottis is seen with the oesophagus beyond it. (c) The cords are also seen.

Figure 5.7

Cardiac compressions performed by encircling the chest, whilst ventilation breaths are given by bag-valve-mask in a 3:1 ratio.

Chapter 6

Figure 6.1

Head-to-toe examination sequence. From Miall, L. (2009)

The Newborn Examination. Paediatrics at a Glance

, 3rd edition, 
Wiley-Blackwell. Reproduced with permission of John Wiley & Sons.

Figure 6.2

Sagittal synostosis. (a) The baby has a palpable ridge on their skull. (b) 3D CT scan of the same child showing fusion of the sagittal suture (arrow).

Figure 6.3

This baby (who is being examined under anaesthetic) has a normal red reflex in their left eye, but an absent red reflex in the right eye (arrow) due to congenital cataract.

Figure 6.4

Severe micrognathia (with tracheostomy). This patient has cerebro-costo-mandibular syndrome.

Figure 6.5

Cystic hygroma of the neck (trans-illuminated).

Figure 6.6

(a) Teratoma of the neck. This child was intubated while still connected to the placental circulation (EXIT procedure) before having surgical excision. (b) MRI scan showing the same lesion (arrow).

Figure 6.7

A radiograph showing multiple vertebral anomalies (arrows).

Figure 6.8

Eliciting the Moro reflex.

Figure 6.9

(a) Talipes equinovarus; (b) talipes calcaneovalgus.

Figure 6.10

Ortolani’s test. The hip cannot be abducted because of posterior dislocation of the femoral head. The hip is pulled upwards and the head clunks into the acetabulum, permitting abduction. Barlow’s test. The adducted hip is pushed downwards and laterally to see whether it is dislocatable. Source: Lawrence Miall, Mary Rudolf, Dominic Smith. Paediatrics at a Glance, 4th Edition. May 2016, ©2016, Wiley-Blackwell. Reproduced with permission of John Wiley & Sons.

Figure 6.11

Arthrogryposis multiplex.

Figure 6.12

Thanatophoric dwarf.

Figure 6.13

Vascular haemangioma.

Figure 6.14

Congenital melanocytic naevus involving the buttock and loin.

Figure 6.15

Mongolian blue spot.

Figure 6.16

Harlequin ichthyosis with severe deep skin cracking.

Figure 6.17

Transient neonatal pustular melanosis.

Figure 6.18

Cutis aplasia of the scalp. Note the extensive area of hair loss, some of which is scabbed over.

Chapter 7

Figure 7.1

Anatomic location of injuries to the head. Source: Tom Lissauer, Avroy A. Fanaroff, Lawrence Miall, Jonathan Fanaroff. Neonatology at a Glance, 3rd Edition. Wiley-Blackwell. Reproduced with permission of John Wiley & Sons.

Figure 7.2

Cephalhaematoma. Note the swelling over the right parietal bone. This child also has hypotonia with a characteristic drooping appearance to the mouth.

Figure 7.3

Right frontal depressed skull fracture (see arrow).

Figure 7.4

Right-sided clavicular fracture in a child born after shoulder dystocia. The baby is also receiving mechanical ventilation.

Figure 7.5

Left-sided facial nerve palsy.

Figure 7.6

Right-sided Erb’s palsy showing the typical ‘waiter’s tip’ position of the hand. Note the unilateral Moro reflex on the left.

Figure 7.7

Bruising to the foot from SaO

2

probe.

Figure 7.8

Chemical burn from aqueous 2% chlorhexidine used prior to UAC insertion in an extreme preterm baby. Reproduced with permission from Lashkari, H.P., Chow, P., Godambe, S. (2011) Aqueous 2% chlorhexidine-induced chemical burns in an extremely premature infant.

Archives of Diseases in Childhood: Fetal and Neonatal Edition

,

97

, F64.© 2011, BMJ Publishing Group Ltd.

Chapter 8

Figure 8.1

Diagram of a DNA double helix.

Figure 8.2

Normal chromosome pattern and number after Giemsa staining. This is an example of a male karyotype. The hashed horizontal line is at the centromere and divides the chromosome into short (p) and long (q) arms.

Figure 8.3

Image showing FISH probes for chromosome 21 (red) and chromosome 13 (green). There are three red signals (abnormal) and two green signals (normal); this patient therefore has trisomy 21.

Figure 8.4

A family pedigree showing autosomal dominant inheritance.

Figure 8.5

A family pedigree showing autosomal recessive inheritance.

Figure 8.6

A family pedigree showing X-linked recessive inheritance.

Chapter 9

Figure 9.1

Total body water and extracellular fluid expressed as percentages of body weight. Redrawn from Dear (1984), with permission from Reed Business Publishing.

Figure 9.2

Hormonal maintenance of lactation. PIF, prolactin-inhibiting factor; PRF, prolactin-releasing factor.

Chapter 10

Figure 10.1

Schematic representation of the clinical features of prenatal TORCH infections.

Figure 10.2

Routes of neonatal cross-infection.

Figure 10.3

Showing position of infant during lumbar puncture while taking care to avoid excessive bending.

Figure 10.4

Equipment required for insertion of a percutaneous intravenous central catheter (PICC). Illustration courtesy of Dr Emmanuel Erinaugha.

Chapter 11

Figure 11.1

Outcomes of all extreme preterm babies born in the UK in 2006.

Chapter 12

Figure 12.1

Monozygotic twins born at 32 weeks. The smaller twin weighed 750 g and the larger 1700 g. The smaller twin shows features of IUGR with relative head sparing (asymmetric IUGR).

Chapter 13

Figure 13.1

Stages of fetal lung development. Reproduced with permission from Attar, M.A., Donn, S.M. (2002) Mechanism of ventilator-induced lung injury in premature infants.

Seminars in Neonatology

,

7

, 353–360; © 2002, Elsevier.

Figure 13.2

Oxygen dissociation curve for fetal haemoglobin (upper red line) and adult haemoglobin (lower blue line).

Figure 13.3

Pressure–volume loop showing compliance of the lung.

Figure 13.4

Flow–volume loop, showing resistance to airflow. The loop on the left shows increased resistance causing impedance to airflow, which has improved after treatment as shown in the loop on the right.

Figure 13.5

Lung volumes. TLC, total lung capacity; VC, vital capacity; RV, residual volume; IC, inspiratory capacity; FRC, functional residual capacity; IRC, inspiratory respiratory capacity; ERC, expiratory respiratory capacity; TV, tidal volume.

Chapter 14

Figure 14.1

Transient tachypnoea of the newborn (TTN). Note streaky bilateral shadows, fluid in the transverse fissure (arrows) and relative cardiomegaly.

Figure 14.2

Incidence of RDS related to gestational age.

Figure 14.3

Schematic representations of two alveoli, demonstrating the Laplace law (see text for details).

Figure 14.4

Chest radiograph showing the characteristic ‘ground glass’ appearance of RDS. Note the ‘air bronchogram’.

Figure 14.5

Chest radiograph showing right-sided tension pneumothorax. Note this has occurred despite a chest drain being in place, suggesting a massive air leak or a blocked chest drain.

Figure 14.6

Chest radiograph showing pneumomediastinum. 
The heart and thymus are outlined by gas.

Figure 14.7

Chest radiograph showing extensive PIE. Note the overinflated chest with flattened diaphragm.

Figure 14.8

Chest radiograph showing left-sided PIE. The mediastinum and right lung are compressed by the overinflated 
left lung.

Figure 14.9

(a) Left-sided pneumothorax in a preterm baby. (b) The same baby after insertion of a 10 Fr pigtail catheter.

Figure 14.10

Chest radiograph showing meconium aspiration syndrome (MAS). There is extensive discrete shadowing throughout both lung fields and hyperinflation.

Figure 14.11

Chest radiograph showing a left-sided diaphragmatic hernia.

Figure 14.12

Variants of tracheo-oesophageal fistula with or without oesophageal atresia. Type (c) accounts for 85% of cases, the others being equally uncommon.

Figure 14.13

Chest radiograph showing severe bronchopulmonary dysplasia.

Chapter 15

Figure 15.1

Neuromuscular pathway for control of respiration.

Figure 15.2

Suggested protocol for the management of apnoea alarm.

Figure 15.3

A normal upper airway. Reproduced with permission from South, M., Isaacs, D. (eds)

Practical Paediatrics

, 7th edition. Elsevier Health Sciences, London.

Figure 15.4

Nasopharyngeal tube used for micrognathia. Reproduced with permission from South, M., Isaacs, D. (eds)

Practical Paediatrics

, 7th edition. Elsevier Health Sciences, London.

Chapter 16

Figure 16.1

Upper and lower centiles for (a) systolic and (b) diastolic blood pressure against gestational age. (c) The change in mean arterial blood pressure (MABP) with postnatal age at different gestational age bands.

Figure 16.2

Flow diagram showing a suggested graded management response to neonatal hypotension.

Figure 16.3

Real-time, two-dimensional echocardiograms of the normal neonatal heart. (a) Parasternal long-axis view. RV, right ventricle; LV, left ventricle; Ao, aorta; LA, left atrium. (b) Parasternal short-axis view showing colour Doppler (left-to-right) flow through patent ductus arteriosus (white arrow). Illustration courtesy of Dr J. Wyllie. (c) Apical four-chamber view, 
RA, right atrium; RV, right ventricle; LV, left ventricle; LA, left atrium.

Figure 16.4

A diagnostic approach to cyanotic CHD.

Figure 16.5

Schematic diagram of simple transposition of the great vessels without VSD.

Figure 16.6

Tetralogy of Fallot.

Figure 16.7

A large mid-muscular ventricular septal defect.

Figure 16.8

Schematic diagram of a hypoplastic left heart.

Chapter 17

Figure 17.1

Cleft lip. (a) At birth the infant has a right-sided cleft lip. (b) The same infant following repair. Pictures courtesy of Mr Alistair Smyth. Reproduced with permission of John Wiley & Sons.

Figure 17.2

Duodenal atresia. Abdominal radiograph showing the ‘double bubble’ appearance.

Figure 17.3

Omphalocoele. Illustration courtesy of Dr Lawrence Miall. Reproduced with permission of Dr Lawrence Miall.

Figure 17.4

Gastroschisis being gradually reduced using a silo.

Figure 17.5

Congenital ascites and umbilical hernia.

Figure 17.6

Schema for the development of NEC.

Figure 17.7

Radiological appearance of NEC. The image shows extensive intramural gas in the bowel and dilated loops of small bowel.

Figure 17.8

Left-sided inguinal hernia.

Figure 17.9

Hypospadius and potential urethra opening sites.

Chapter 18

Figure 18.1

Longitudinal ultrasound view of fetal abdomen showing bilateral renal pelvocalyceal dilatation. Illustration courtesy of Dr R. Cincotta.

Figure 18.2

Management of fetal renal pelvis dilatation.

Figure 18.3

Suprapubic aspiration of urine from the bladder. The needle should be aimed slightly superiorly in the midline and 0.5 cm above the pubis.

Chapter 19

Figure 19.1

Summary of neonatal bilirubin metabolism.

Figure 19.2

Phototherapy for hyperbilirubinaemia.

Figure 19.3

NICE clinical guideline: treatment threshold for babies with neonatal jaundice ≥38 weeks’ gestation.

Figure 19.4

Approach to the jaundiced infant.

Chapter 20

Figure 20.1

Physiological anaemia. The two graphs show the normal fall in haemoglobin with postnatal age in mature and premature infants.

Figure 20.2

The interrelationship between polycythaemia and hyperviscosity and their contribution towards clinical signs. CNS, central nervous system; GFR, glomerular filtration rate.

Chapter 21

Figure 21.1

Metabolic pathways involved in gluconeogenesis.

Figure 21.2

Characteristic appearance of the macrosomic infant of a poorly controlled diabetic mother. Note the right-sided brachial plexus injury (Erb’s palsy), arising from shoulder dystocia.

Figure 21.3

Radiograph of an infant’s forearm and wrist, showing the metaphyseal flaring of neonatal rickets (arrow).

Figure 21.4

A simplified diagram to illustrate the synthesis of adrenal hormones. The asterisk represents the enzyme 17-α-hydroxydehydrogenase.

Figure 21.5

Flow diagram showing a scheme for investigating infants with ambiguous genitalia.

Figure 21.6

Representation of metabolic pathways with a negative feedback loop.

Figure 21.7

Metabolism of phenylalanine. The broken arrow represents the enzyme defect in phenylketonuria.

Chapter 22

Figure 22.1

The sequence of brain development.

Figure 22.2

Occipital encephalocoele, prior to surgical repair.

Figure 22.3

The varieties of spina bifida.

Figure 22.4

Lumbosacral myelomeningocoele. Note the baby has talipes.

Figure 22.5

Premature suture closure leading to craniostenosis. (a) Scaphocephaly (sagittal suture); (b) turricephaly (coronal suture); (c) plagiocephaly (single lambdoid suture). The dotted line indicates different sutural synostosis, Coronal and lambdoid sutures can be involved on one or both sides, giving different shapes.

Figure 22.6

Diagram to show intracerebral drainage of cerebrospinal fluid. Reproduced from Levene 1987, with permission of Churchill Livingstone, Elsevier.

Figure 22.7

Coronal ultrasound scan showing massive dilatation of both lateral ventricles and the third ventricle.

Figure 22.8

Indication for intervention for significant ventriculomegaly. The lower line is the 97th centile for normal ventricular size. The upper line defines ventricular dilatation severe enough to require treatment.

Figure 22.9

Post-mortem specimen showing bilateral intraventricular haemorrhage with ventricular dilatation.

Figure 22.10

Coronal ultrasound scan showing massive left-sided IVH with venous infarction of the left parietal lobe with porenchephalic cyst developing (arrow).

Figure 22.11

Cystic periventricular leukomalacia (PVL). (a) Cerebral ultrasound showing PVL; there is bilateral periventricular ‘flare’ with cysts on the left side (arrowed) which appeared at 14 days of life; (b) T2-weighted MRI scan on the same patient 6 days later shows extensive bilateral cystic PVL (arrows).

Figure 22.12

Neonatal stroke. MRI scan showing ischaemic infarction of the brain (dark) in the territory of left middle cerebral artery.

Figure 22.13

The prognostic values of different forms of aEEG tracings in babies with hypoxic–ischaemic encephalopathy. While the top and middle tracings are mostly indicative of good prognosis, the suppressed amplitude with continuous low voltage with seizure activity (burst suppression) as seen in the bottom panel is invariably associated with a worst prognosis in terms of death and neurodisability.

Figure 22.14

Abnormality in the thalamic nuclei (arrows) in a term baby indicating a poor prognosis following acute intrapartum asphyxia.

Figure 22.15

Trace from a cerebral function monitor. There are frequent electroconvulsive seizures (red arrows). The clinically evident seizures are marked in the upper panel with black arrows, showing a degree of electroconvulsive dissociation. The blue arrow indicates the onset of seizure activity on the raw EEG panel. The bottom panel shows the raw EEG trace present at the point in time marked by the black arrow on the top panel. This shows the start of a seizure

Figure 22.16

An infant with severe hypotonia, showing the characteristic ‘frog’ posture.

Chapter 23

Figure 23.1

Stage 3 retinopathy of prematurity (ridging and vascular proliferation) with plus disease (tortuosity of posterior retinal vessels).

Chapter 24

Figure 24.1

Heat loss. (a) By conduction; (b) by convection; (c) by radiation; (d) by evaporation. Reproduced from Warren, I. (2010)

Nursing the Neonate

, 2nd edition, Wiley Blackwell.

Figure 24.2

Demonstration of the use of a plastic wrap and hat to aid thermoregulation in the newborn preterm infant. Reproduced with permission of Dr Wood.

Figure 24.3

(a) Neutral thermal environment during the first week of life, calculated from the measurements. Dewpoint of the air 18 °C, flow 10 l min

–1

; (b) Neutral thermal environment (°C) from day 7 to day 35. Dewpoint of the air 18 °C. flow 10 l min

–1

. Body weight is current weight. Values for body weight >2.0 kg are calculated by extrapolation.

Source:

Sauer PJ, Dane HJ, Visser HK. New standards for neutral thermal environment of healthy very low birthweight infants in week one of life. Arch Dis Child. 1984 Jan;59(1):18-22. Reproduced with permission of BMJ Publishing Group Ltd.

Figure 24.4

Three designs of intensive care incubator. (a) Closed incubator; (b) hybrid; (c) open platform.

Figure 24.5

Developmental care within the neonatal nursery.

Figure 24.6

(a) Kangaroo care. Reproduced with permission of Rady Children’s Hospital – San Diego; (b) Skin-to-skin contact. Reproduced with permission from Neama Firth.

Chapter 27

Figure 27.1

Corrected postnatal ages at which disabilities become evident in VLBW infants.

Chapter 30

Figure 30.1

A typical Limitation of Treatment Agreement (LOTA) agreement.

Figure 30.2

Memory box. Source: Tom Lissauer, Avroy A. Fanaroff, Lawrence Miall, Jonathan Fanaroff. Neonatology at a Glance, 3rd Edition August 2015, ©2014, Wiley-Blackwell. Reproduced with permission of John Wiley & Sons.

Guide

Cover

Table of Contents

Preface

Pages

vii

vii

viii

ix

xi

xii

1

2

3

4

6

7

8

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

78

79

80

81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

97

98

99

100

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

284

285

286

287

288

289

290

291

292

293

294

295

296

297

298

300

301

302

303

304

305

306

307

308

309

310

311

312

313

314

315

316

317

319

320

321

323

Preface to the Sixth Edition

Neonatology is coming of age as a speciality — when the First Edition of this book was published 30 years ago, neonatal medicine was evolving rapidly and the emphasis was rightly on improving survival, especially at the margins of extreme prematurity. Now, survival is greater than 90% down to 28 weeks, and survival at 24 weeks — previously regarded as the threshold of viability — exceeds 60%.

With this improvement in survival, emphasis has begun to turn to the quality of care, quality of family support, and to the longer-term outcomes of graduates of the neonatal intensive care unit. Parents and siblings are now routinely welcomed into the nursery, whereas 30 years ago they may have been restricted in their visiting, and family-centred and family integrated care is becoming the normal. There is an increasing emphasis on risk reduction and minimizing harm — whether through hospital-acquired infections, injury from lines and procedures, or preventing ventilator-associated lung injury with the use of minimally invasive ventilation. There is also a greater recognition of the subtle but significant developmental and health challenges faced by only moderately pre-term babies, who are considerably greater in number than the extreme preterm babies.

To reflect this evolution this book has also evolved, with new chapters on palliative and end-of-life care, a greater emphasis on developmental and family care, and comprehensively updated chapters to include the latest developments in diagnostic imaging and genetic testing available. We believe that Essential Neonatal Medicine offers a comprehensive introduction to modern neonatology for trainee doctors, neonatal nurses, nurse practitioners and allied health professionals. We thank the many colleagues who have made it possible.

Dr Sunil SinhaDr Lawrence MiallDr Luke Jardine

Acknowledgements

We would like to thank all the many colleagues and families who have contributed to this edition. In particular, Mr Andrew Breeze for reviewing the obstetric chapter, and Dr Jayne Shillito, Dr Mike Weston, Dr Fiona Wood, Dr Shalabh Garg, Dr Sam Richmond, Dr Jonathan Wyllie, Mr Roly Squire, Mr Vernon Long, Dr Scott Peterson and Dr Liz McKechnie for providing clinical images.

This edition of the book would also not have been possible without the efforts of many ‘behind the scenes’ individuals, including Jennifer Seward (Senior Project Editor) and Loan Nguyen (Senior Editorial Assistant), and the editors are grateful to them for their patience and guidance.

We would especially like to thank our families for their support with this project and their understanding during the many evenings we spent writing this book.

And finally, we are indebted to the babies and their families that it has been our privilege to treat, who have taught us so much over the years.

Preface to the First Edition

There has been an explosion of knowledge over the last decade in fetal physiology, antenatal management and neonatal intensive care. This has brought with it confusion concerning novel methods of treatment and procedures as well as the application of new techniques for investigating and monitoring high-risk neonates. The original idea for this book was conceived in Brisbane, and a Primer of Neonatal Medicine was produced with Australian conditions in mind. We have now entirely rewritten the book, and it is the result of cooperation between Australian and British neonatologists with, we hope, an international perspective.

We are aware of the need for a short book on neonatal medicine which gives more background discussion and is less dogmatic than other works currently available. We have written this book to give more basic information concerning physiology, development and a perspective to treatment which will be of value equally to neonatal nurses, paediatricians in training, medical students and midwives. Whilst collaborating on a project such as this we are constantly aware of the variety of ways for managing the same condition. This is inevitable in any rapidly growing acute speciality, and we make no apologies for describing alternative methods of treatment where appropriate. Too rigid an approach will be to the detriment of our patients!

A detailed account of all neonatal disorders is not possible but common problems and their management are outlined giving an overall perspective of neonatology. Attention has been given to rare medical and surgical conditions where early diagnosis and treatment may be lifesaving. It is easy to be carried away with the excitement of neonatal intensive care and forget the parents sitting at the cotside. Our approach is to care for the parents as well as their baby, and we have included two chapters on parent–infant attachment as well as death and dying. The final chapter deals with practical procedures and gives an outline of the commonly performed techniques used in the care of the high-risk newborn. We have also provided an up-to-date neonatal Pharmacopoeia as well as useful tables and charts for normal age-related ranges.

Malcolm I. LeveneDavid I. TudehopeM. John Thearle

Abbreviations

ABR

auditory brainstem response

ADHD

attention deficit hyperactivity disorder

ALTE

acute life-threatening events

ART

assisted reproductive technology

ASD

atrial septal defect

BE

base excess

BPD

bronchopulmonary dysplasia

CAH

congenital adrenal hyperplasia

CCAM

congenital cystic adenomatous malformation

CDH

congenital diaphragmatic hernia

CFM

cerebral function monitoring

CHARGE

c

oloboma,

h

eart defects, choanal

a

tresia,

r

etardation,

g

enital and/or urinary abnormalities,

e

ar abnormalities

CHD

congenital heart disease

CLD

chronic lung disease

CPAP

continuous positive airway pressure

CVP

central venous pressure

DDH

developmental dysplasia of the hip

DIC

disseminated intravascular coagulation

EBM

expressed breast milk

ELBW

extremely low birthweight

FASD

fetal alcohol spectrum disorder

FES

fractional excretion of sodium

FHR

fetal heart rate

FRC

functional residual capacity

GFR

glomerular filtration rate

GIFT

gamete intrafallopian transfer

GORD

gastro-oesophageal reflux disease

HCV

hepatitis C virus

HIE

hypoxic–ischaemic encephalopathy

HMF

human milk fortifiers

ICH

intracerebral haemorrhage

IDM

infants of diabetic mothers

IPPV

intermittent positive pressure ventilation

ITP

idiopathic thrombocytopenic purpura

IUGR

intrauterine growth restriction

IVF

in vitro

fertilization

IVH

intraventricular haemorrhage

LBW

low birthweight

LMP

last menstrual period

LVH

left ventricular hypertrophy

MAS

meconium aspiration syndrome

NAS

neonatal abstinence syndrome

NCPAP

nasal continuous positive airway pressure

NICU

neonatal intensive care unit

NIPPV

non-invasive positive pressure ventilation

NTD

neural tube defects

PCV

pneumococcal conjugate vaccine

PDA

patent ductus arteriosus

PEEP

positive end-expiratory pressure

PET

pre-eclampsia

PICC

peripherally inserted central catheter

PIE

pulmonary interstitial emphysema

PIP

peak inspiratory pressure

PMR

perinatal mortality rate

PPHN

persistent pulmonary hypertension of the newborn

PROM

premature rupture of membranes

RDS

respiratory distress syndrome

ROP

retinopathy of prematurity

RVH

right ventricular hypertrophy

SGA

small for gestational age

SIDS

sudden infant death syndrome

SLE

systemic lupus erythematosus

TAR

thrombocytopenia with absent radii

TGA

transposition of the great arteries

ToF

tetralogy of Fallot

TORCH

t

oxoplasmosis,

o

ther infections,

r

ubella,

c

ytomegalovirus,

h

erpes simplex virus

TPN

total parenteral nutrition

TSH

thyroid-stimulating hormone

TTN

tachypnoea of the newborn

TTTS

twin-to-twin transfusion syndrome

UAC

umbilical arterial catheter

UVC

umbilical venous catheter

VACTERL

v

ertebral anomalies,

a

nal atresia,

c

ardiovascular anomalies,

t

racheoesophageal fistula, o

e

sophageal atresia,

r

enal and/or radial anomalies,

l

imb defects

VAPS

volume-assured pressure support

VCV

volume-controlled ventilation

VILI

ventilator-induced lung injury

VLBW

very low birthweight

VSD

ventricular septal defect

VUR

vesico-ureteric reflux

WHO

World Health Organization

How to use your textbook

Features contained within your textbook

Every chapter begins with a list of Key topics.

  The website icon indicates that you can find accompanying self-assessment resources on the book's companion website.

About the companion website

This book has a companion website at:

  www.essentialneonatalmed.com

with:

Figures from the book in PowerPoint format

Interactive self-assessment questions and answers

Further reading list

CHAPTER 1The fetus, placenta and changes at birth

Key topics

Placental function

Fetal homeostasis

Fetal circulation

Assessment of fetal well-being

Screening during pregnancy

Fetal monitoring during labour

Fetal compromise

Introduction

The discipline of ‘perinatal medicine’ spans the specialities of fetal medicine and neonatology. The obstetrician must have a thorough knowledge of pregnancy and its effects on the mother and fetus, as well as fetal development and physiology. The neonatologist specialises in the medical care of the infant immediately after birth, but must also have a thorough understanding of fetal development and physiology. This chapter reviews fetal assessment and physiology to provide the paediatrician and neonatal nurse with a better understanding of normal perinatal adaptation, and the adverse consequences arising from maladaptation.

Placental function

The placenta is a fetal organ that has three major functions: transport, immunity and metabolism.

The uterus is supplied with blood from the uterine arteries, which dilate throughout pregnancy, increasing blood supply 10-fold by term. Maternal blood bathes the intervillous space and is separated from fetal blood by the chorionic plate. Transport of nutrients and toxins occurs at this level. Oxygenated fetal blood in the capillaries of the chorionic plate leaves the placenta via the umbilical vein to the fetus (Fig. 1.1).

Figure 1.1 Diagram of placental structures showing blood perfusion.

Transport

The placenta transports nutrients from the mother to the fetus, and waste products in the other direction. This occurs in a number of ways, including simple diffusion (for small molecules) and active transport, which is used for larger molecules. The placenta is crucially also responsible for gaseous exchange of oxygen and carbon dioxide. Oxygen diffuses from the mother (PO2 = 10–14 kPa, 75–105 mmHg) to the fetus (PO2 = 2–4 kPa, 15–30 mmHg), where it binds to fetal haemoglobin. This has a higher affinity for oxygen than maternal haemoglobin for a given PO2. The dissociation of oxygen from maternal haemoglobin is also facilitated by a change in maternal blood pH.

Immunity

The placenta trophoblast prevents the maternal immune system from reacting against ‘foreign’ fetal antigens. Rejection does not occur because the trophoblastic cells appear to be non-antigenic, although it is known that fetal cells can cross into the maternal circulation where they can trigger an immune reaction (e.g. rhesus haemolytic disease). Maternal IgG antibody – the smallest of the immunoglobulins – can cross the placenta, where it provides the newborn with innate immunity to infectious diseases. These IgG antibodies can also cause perinatal disease such as transient hyperthyroidism (see Chapter 21).

CLINICAL TIP

Because IgG antibody crosses the placenta, the presence of IgG antibody in the newborn’s blood does not necessarily mean it has been congenitally infected. This is of particular relevance when testing newborns for HIV infection, where a positive IgG may just reflect maternal exposure. Instead, direct tests (e.g. viral RNA by PCR) are required (see Chapter 10).

Metabolism

The placenta is metabolically active and produces hormones, including human chorionic gonadotropin (hCG) and human chorionic thyrotropin (hCT). It also detoxifies drugs and metabolites. Oestriol cannot be produced by the placenta alone. This is done by the fetal liver and adrenal glands. The metabolites are then sulphated by the placenta to form oestrogens, one of which is oestriol.

Because of its metabolic activity, the placenta has very high energy demands and consumes over 50% of the total oxygen and glucose transported across it.

Fetal homeostasis

The placenta is an essential organ for maintaining fetal homeostasis, but the fetus is capable of performing a variety of physiological functions:

The liver produces albumin, coagulation factors and red blood cells.

The kidney excretes large volumes of dilute urine from 10–11 weeks’ gestation, which contributes to amniotic fluid.

Fetal endocrine organs produce thyroid hormones, corticosteroids, mineralocorticoids, parathormone and insulin from 12 weeks’ gestation.

Some immunoglobulins are produced by the fetus from the end of the first trimester.

Fetal circulation

The fetal circulation is quite different from the newborn or adult circulation. The umbilical arteries are branches of the internal iliac arteries. These carry deoxygenated blood from the fetus to the placenta, where it is oxygenated as it comes into close apposition with maternal blood in the intervillous spaces. Oxygenated fetal blood is carried in the single umbilical vein, which bypasses the liver via the ductus venosus to reach the inferior vena cava (IVC). It then passes into the IVC and enters the right atrium as a ‘jet’, which is shunted to the left atrium across the foramen ovale (Fig. 1.2). From here it passes into the left ventricle and is pumped to the coronary arteries and cerebral vessels. In this way the fetal brain receives the most oxygenated blood. Some relatively deoxygenated blood is pumped by the right ventricle into the pulmonary artery, but the majority bypasses the lungs via the ductus arteriosus (DA) to flow into the aorta, where it is carried back to the placenta. Only 7% of the combined ventricular output of blood passes into the lungs. The right ventricle is the dominant ventricle, ejecting 66% of the combined ventricular output.

Figure 1.2 Diagram of the fetal circulation through the heart and lungs, showing the direction of flow through the foramen ovale and ductus arteriosus.

In summary, there are three shunts:

The

ductus venosus

bypasses blood away from the liver to the IVC.

The

foramen ovale

shunts blood from the right atrium to the left atrium.

The

ductus arteriosus

shunts blood from the pulmonary artery to the aorta.

The last two shunts only occur because of the very high fetal pulmonary vascular resistance and the high pulmonary artery pressure that is characteristic of fetal circulation.

Umbilical vessels

There are two umbilical arteries and one umbilical vein, surrounded by protective ‘Wharton’s jelly’. In 1% of babies there is only one umbilical artery, and this may be associated with growth retardation and congenital malformations, especially of the renal tract. Chromosomal anomalies are also slightly more common.

CLINICAL TIP

It used to be common practice to arrange a renal ultrasound if there was only one umbilical artery – this is no longer required as antenatal imaging of the kidneys is sufficiently high quality.

Assessment of fetal well-being

Assessment of fetal well-being is an integral part of antenatal care. It includes diagnosis of fetal abnormality, assessment of the fetoplacental unit and fetal maturity, and the monitoring of growth and well-being in the third trimester and during labour (Fig. 1.3).

Figure 1.3 A timeline for fetal assessment and monitoring during pregnancy.

Assessment of maturity

Ultrasound

Early measurement of fetal size is the most reliable way to estimate gestation, and is considered to be even more reliable than calculation from the date of the last menstrual period (LMP). Ultrasound measurements that correlate well with gestational age include crown–rump length (CRL; until 14 weeks), biparietal diameter (BPD) or head circumference (HC) and femur length. The HC measurement at 14–18 weeks appears to be the best method for assessing the duration of pregnancy. In in-vitro fertilization (IVF) pregnancy the date of fertilization is used to calculate the gestation.

Assessment of fetal growth and well-being

Clinical assessment

Monitoring fundal height is a time-honoured method of 
assessing fetal growth. Unfortunately, up to 50% of small-
for-gestational age fetuses are not detected clinically.

Ultrasound

Serial estimates of BPD, HC, abdominal circumference and femur length are widely used to monitor growth, often on customized fetal growth charts. In fetuses suffering intrauterine growth restriction (IUGR), head growth is usually the last to slow down. Estimating fetal weight by ultrasound has become very accurate and provides critical information for perinatal decision-making about the timing of delivery.

Ultrasound imaging and Doppler blood flow

The location of the placenta can be confidently established using ultrasound. This is important to rule out placenta previa (a cause of antepartum haemorrhage) and to avoid cutting through the placenta at caesarean section. Doppler flow velocity waveforms of the umbilical artery are now used to assess fetal well-being. In near-term IUGR fetuses, abnormal Doppler waveforms are a reliable prognostic feature. As fetal blood flow becomes compromised there is reduced, then absent or reversed flow during diastole. Reversed diastolic flow may be an ominous sign and is associated with a high risk of imminent fetal demise (see Fig. 1.4). If end-diastolic flow (EDF) is absent, detailed Doppler studies of the middle cerebral artery (MCA) and ductus venosus are indicated. The umbilical artery Doppler flow pattern is used to determine the frequency of ongoing surveillance. In more preterm babies (32–37 weeks), EDF may be maintained even in severe compromise. Evidence of cerebral redistribution should trigger intensive regular monitoring. Timing of delivery will be based on Doppler patterns, gestation and estimated fetal weight. Doppler measurement of peak systolic blood flow velocity in the MCA is useful in the assessment of fetal anaemia and isoimmunization. As anaemia becomes severe, the velocity increases (see Chapter 20).

Figure 1.4 Doppler measurement of blood flow in the fetal umbilical artery. The left-hand panel shows normal forward flow throughout the cardiac cycle. The right-hand panel shows pathological reversed flow during diastole (see arrow).

Amniotic fluid volume

Amniotic fluid (liquor) is easily seen on ultrasound, and the ‘single deepest pool’ or maximum pool size in four quadrants is measured (amniotic fluid index). This is often combined with non-stress testing (NST), counting movement and breathing. Both excess (polyhydramnios) and reduced (oligohydramnios) amniotic fluid volumes can be associated with adverse fetal outcome (see Table 1.1). Some centres assess fetal well-being using the ‘biophysical profile scan’, which includes fetal movements and tone and liquor volume.

Table 1.1 Causes of abnormal amniotic fluid volumes and fetal consequences.

Causes of Polyhydramnios

Causes of 
Oligohydramnios

Maternal diabetes

Preterm rupture of membranes (PPROM)

Twin-to-twin transfusion syndrome (recipient)

Twin-to-twin transfusion (donor)

Obstruction to swallowing or absorption of liquor

Oesophageal atresia

Duodenal atresia

Abnormal swallowing

Abnormal swallowing

Congenital myotonic dystrophy

Trisomy 18

Severe fetal growth restriction (IUGR)

Renal anomalies

Renal agenesis (Potter’s syndrome) or severe renal dysplasia.

ARPCKD

Posterior urethral valves 
(in males)

Chromosomal anomalies

Fetal consequences of polyhydramnios

Fetal consequences of oligohydramnios

Increased risk of preterm labour and PPROM

Increased risk of pulmonary hypoplasia

Abnormal presentation (e.g. transverse or breech)

If severe, risk of fetal deformation

ARPCKD, Autosomal recessive polycystic kidney disease

Fetal breathing movements

The breathing movements of the fetus show marked variability. The fetus breathes from about 11 weeks’ gestation, but this is irregular until 20 weeks. Fetal breathing promotes a tracheal flux of fetal lung fluid into the amniotic fluid. An absence of amniotic fluid (oligohydramnios) can lead to pulmonary hypoplasia. Abnormal gasping respiration, extreme irregularity of breathing in a term fetus and complete cessation of breathing are visible by ultrasound.

Fetal heart rate monitoring, non-stress test and biophysical profile

The response of the fetal heart to naturally occurring Braxton Hicks contractions or fetal movements provides information on fetal health during the third trimester. A normal fetal heart trace has a baseline heart rate of 110–160 beats per minute, with good beat-to-beat variability and at least two accelerations and no decelerations in a 20-minute period. If abnormal, a further assessment with ultrasound is recommended to gather further information about fetal well-being. Depending on gestation, an abnormal fetal heart rate will sometimes necessitate early delivery of the baby.

In late pregnancy the biophysical profile combines the NST and ultrasound assessment of fetal movements. A score (2) is given for each of: heart rate accelerations, fetal breathing movements, fetal limb movements, movement of the trunk and adequate amniotic fluid depth. A normal well fetus will score 10/10, and a score of less than 8 is abnormal.

Screening during pregnancy

Maternal blood screening

Screening programmes vary from country to country. In the UK, all pregnant women are routinely screened for syphilis, hepatitis B, immunity to rubella and haemoglobinopathies (sickle cell disease, thalassaemia), and HIV screening is strongly encouraged.

Fetal imaging

Ultrasound examination of the fetus for congenital abnormalities is now offered as a routine procedure. Major malformations of the central nervous system, bowel, heart, genitourinary system and limbs should be detected. Some disorders, such as twin-to-twin transfusion, pleural effusion and posterior urethral valves are amenable to fetal ‘surgery’. In-utero surgery for congenital diaphragmatic hernia remains experimental. Advanced ‘4D’ (3D seen in real time) ultrasonography allows visualization of the external features of the fetus, such as the presence of cleft lip (see Fig. 1.5).

Figure 1.5 Cleft lip. Illustration courtesy of Dr Jason Ong.

Fetal magnetic resonance imaging (MRI) is now feasible and appears safe in pregnancy. The large field of view, excellent soft-tissue contrast and multiple planes of construction make MRI an appealing imaging modality to overcome the problems with ultrasound in cases such as maternal obesity and oligohydramnios, but MRI cannot be used for routine screening. It is useful in the assessment of complex anomalies such as urogenital and spinal anomalies, some fetal cardiac disorders, complex head and neck malformations (Fig. 1.6) and congenital diaphragmatic hernia. Its main use is to provide further information about fetal brain development when abnormalities are suspected on ultrasound.

Figure 1.6 Fetal MRI scan (coronal view) showing large cystic hygroma on the left side of the neck (arrow) and an associated pleural effusion (arrow). Illustration courtesy of Dr Mike Weston.

Down’s syndrome screening

Trisomy 21 affects 1 in 600 fetuses and 1 in 1000 live births. The incidence rises with maternal age (from 1 in 880 at 30 years to 1 in 100 at 40 years), but as more younger women are pregnant screening in the UK is offered to all pregnant women, regardless of age. The screening tests vary and are summarized in Table 1.2. If the risks after screening are high, then a diagnostic test (amniocentesis or chorionic villus sampling; CVS) is offered.

Table 1.2 Screening tests for Down’s syndrome in UK.

Screening test

Timing (weeks of gestation)

Comments

Nuchal fold thickness

11–13

Measures translucency at nape of neck, which is increased in trisomy 18 and some cardiac defects. Gives age-related risk.

NIPT (Non-invasive prenatal testing)

10–22

Measures cell-free fetal DNA in the maternal circulation and can test for Trisomy 21 and other aneuploidies. Sensitivity is >99% and false positive rate 0.2%. Does not screen for neural tube defects. Only requires a maternal blood sample.

Triple test AFP hCG Oestriol

10–14

Gives age-related risk. AFP very high with neural tube defects.

Combined test Nuchal fold hCG h-PAPP

11–13

Biochemical screening with nuchal fold measurement to give age-related risk.

Quadruple test hCG AFP Oestriol Inhibin A

15–20

Suitable for late booking when nuchal fold measurement no longer reliable. Gives age-related risk.

AFP, alpha-fetoprotein; hCG, human chorionic gonadotropin; 
PAPP, pregnancy-associated plasma protein A.

CLINICAL TIP

It is important to remember that screening tests give a risk for Down’s syndrome (higher or lower than the age-related risk), but they do not give a definitive diagnosis. Some parents find it very difficult to understand that even if the risk is only 1 in 100, they may still be the couple that go on to have an affected child. Parents need to be counselled carefully before undertaking screening.

Amniocentesis

Amniocentesis is valuable for the diagnosis of a variety of fetal abnormalities. Trisomy 13, 18 and 21 can be detected by PCR within 48 h, and the cells cultured for chromosome analysis (14 days) or to study enzyme activity. Ultrasound-guided amniocentesis is undertaken by passing a needle through the anterior abdominal wall into the uterine cavity. The risk of miscarriage is less than 1%. Larger volumes of amniotic fluid may be removed (amnioreduction) as a treatment for polyhydramnios, although this treatment may need to be repeated frequently.

Chorionic villus sampling

CVS involves the transcervical or transabdominal passage of a needle into the chorionic surface of the placenta after 11 weeks’ gestation to withdraw a small sample of tissue. Because of the 1% risk of miscarriage, the test is reserved for the detection of genetic or chromosomal abnormalities in at-risk pregnancies, rather than as a mere screening test. Preliminary chromosomal results can be obtained within 24–48 hours by fluorescence in-situ hybridization (FISH) or quantitative PCR. Direct analysis requires cell culture (14 days), but comparative genomic hybridization (CGH) array testing is now used in most laboratories to analyze the chromosomes in detail.

Fetal blood sampling (cordocentesis)

Fetal blood sampling is an ultrasound-guided technique for sampling blood from the umbilical cord to assist in the diagnosis of chromosome abnormality, intrauterine infection, coagulation disturbance, haemolytic disease or severe anaemia. It can also be used for treatment, with in-utero transfusion of packed red blood cells during the same procedure. There is a 1% risk of fetal death, although this can be higher in babies who are already hydropic.

Fetal monitoring during labour

Intrapartum monitoring

In low-risk pregnancies, intermittent auscultation of the fetal heart rate (FHR) is all that is required. Continuous electronic monitoring of the FHR can be performed non-invasively with a cardiotocograph (CTG) strapped to the abdominal wall, or invasively with a fetal scalp electrode.

The CTG trace allows observation of four features:

Baseline heart rate

Beat-to-beat variability

Decelerations:

Early

: slowing of the FHR early in the contraction with return to baseline by the end of the contraction.

Late

: repetitive, periodic slowing of FHR with onset at middle to end of the contraction.

Variable

:

v

ariable, intermittent slowing of FHR with rapid onset and recovery.

Prolonged

: abrupt fall in FHR to below baseline lasting at least 60–90 s; pathological if last >3 min.

Accelerations

: transient increases in FHR >15 bpm lasting 15 s or more. These are normal and are reassuring. The significance of absent accelerations as a single feature is not known.

The interpretation of the CTG must then be classified as normal, non-reassuring or abnormal (Box 1.1; see also Table 1.3 and Fig. 1.7a–d).

Table 1.3 Features of an intra-partum CTG (NICE 2014).

What to look for on the CTG

Baseline heart rate (bpm)

Variability around baseline

Decelerations

Normal or ‘reassuring’

100–160

5 bpm or more

None or early

‘Non- reassuring’

161–180

<5 bpm for 30–90 min

Variable decelerations:

Dropping from baseline by ≤60 bpm and taking <60 s to recover.

Present for over 90 min.

Occurring with more than half of all contractions.

OR

Variable decelerations:

Dropping from baseline by >60 bpm or taking >60 s to recover.

Present for up to 30 min.

Occurring with more than half of all contractions.

OR

Late decelerations (at or after the peak of the contraction):

Present for up to 30 min.

Occurring with more than half of contractions.

Abnormal

Above 180orbelow 100 bpm

<5 bpm for over 90 min

Non-reassuring variable decelerations (see above) which are:

Still observed 30 min after starting conservative measures.

Occurring with more than half of contractions.

OR

Late decelerations:

Present for over 30 min.

Does not improve with conservative measures.

Occurs with over 50% of contractions.

OR