OXFORD HANDBOOK OF CLINICAL SPECIALTIES

OXFORD HANDBOOK OF CLINICAL SPECIALTIES

NINTH EDITION

JUDITH COLLIER MURRAY LONGMORE KEITH AMARAKONE

3

3

Great Clarendon Street, Oxford OX26DP

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© Oxford University Press, 2013

The moral rights of the authors have been asserted

First published 1987 Fifth edition 1999 Translations: ^Greek Second edition 1989 Sixth edition 2003 Spanish Romanian Third edition 1991 Seventh edition 2006 German Russian Polish Fourth edition 1995 Eighth edition 2008 Hungarian Portuguese 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, without the prior permission in writing of Oxford University Press, or as expressly permitted by law, by licence or under terms agreed with the appropriate reprographics rights organization. Enquiries concerning reproduction outside the scope of the above should be sent to the Rights Department, Oxford University Press, at the address above.

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Typeset by GreenGate Publishing Services, Tonbridge, UK; printed in China on acid-free paper through CC Off set Printing Co. Ltd ISBN978-0-19-959118-3

Drugs

Except where otherwise stated, recommendations are for the non-pregnant adult who is not breastfeeding. To avoid excessive doses in obese patients it may be best to calculate doses on the basis of ideal body weight (IBW): see p621.

We have made every eff ort to check this text, but it is still possible that drug or other errors have been missed. OUP makes no representation, express or implied, that doses are correct. Readers are urged to check with the most up-to-date product information, codes of conduct, and safety regulations. The authors and the publishers do not accept responsibility or legal liability for any errors in the text, or for the misuse or misapplication of material in this work.

For updates/corrections, see oup.co.uk/academic/medicine/handbooks/updates.

Contents

Front cover Back cover

Drugs ii

Preface to the ninth edition iv Preface to the fi rst edition v Confl icts of interest: none declared v Understanding our patients vi

What happens when ward rounds collide? vii Dedication viii

Acknowledgments ix How to use this book x A note on the use of pronouns x Symbols and abbreviations xi

1 Obstetrics 1

2 Paediatrics 98

3 Gynaecology 240

4 Psychiatry 312

5 Ophthalmology 410

6 Primary care 466

7 Ear, nose and throat diseases 534

8 Dermatology 582

9 Anaesthesia 612

10 Unusual eponymous syndromes 638 1 1 Orthopaedics and trauma 656 12 Pre-hospital immediate care 790

Index 817

The content of each chapter is detailed on each chapter’s fi rst page.

iv

Preface

T

his is the fi rst medical textbook to take the health of its readers serious- ly on the grounds that the health of one person (a patient) must not be bought at the expense of another (their doctor). It is an unsettling paradox that when we study medicine our own health goes out of the window (fi g 1), with long hours of coal-face working often without joy or sustenance as our health is shattered by the weight of an over-full curriculum (no doubt because there are too many organs and we know far too much about them).

What can a book do about this defenestration (fi g 1)? First of all the ideal book can (must!) be brief with a

clear distinction between work and play. Secondly, such a book must furnish the mind: as we drill down into the minute structure of dis- ease, there must be a correspond- ing search for the macroscopic, the human, and the universal. This book intends to make plain the idea that for every such spiral of down-drill- ing, there is a corresponding upward spiral (the swarf, fi g 2) towards the

infi nite—and we aim the help the reader fi nd the jumping-off point where these spirals intersect, so that the movement down (reductionism) is complemented by a movement up (integrative medicine). Can this infl uence the heath of our readers? The answer lies in a single

word: enlightenment.

The spiral illuminations at the be- ginning of each chapter (and scat- tered throughout the book) remind us to follow the movement up as well as the movement down. Fol- low the swarf! We should do this in our consultations, as well as in our reading. Never pass over an oppor- tunity to widen the horizons of your patients, or to have your own hori- zons widened by your patient: what better way is there of reducing the size of their (and our) insoluble prob- lems? Here, it is enough to point out that the well-furnished mind confers resilience to the body. We all know

that stress brings on physical disease—and from this premise it is a short step to accept that a resilient mind is central to maintaining heath. We aim to fi nd magnetic correspondences in the jumping-off points between the down- ward-drilling helix and the upward-spinning swarf-spirals using philosophy, literature, humour, and tinctures of hope. Ultimately we would like readers to develop their own methods, thereby converting passive acceptance of an overfull curriculum into wealth, life, and beauty.

JABC, KM&JML—Preface to the 9^th edition—Cape Clear Fig 1. Defenestration

Fig 2. Swarf

“The way up is the way down…

Whether on the shores of Asia, or in the Edg- ware Road.”

The dry salvagesTS Eliot; 1941

v

Preface to the 1

^st

Edition

W

hen someone says that he is ‘doing obstetrics’—or whatever, this should not hide the fact that much more is being done besides, not just a little of each of medicine, psychiatry, gynaecology and paediatrics, but also a good deal of work to elicit and act upon the patient’s unspoken hopes and fears. At the operating table he must concentrate minutely on the problem in hand; but later he must operate on other planes too, in social and psychologi- cal dimensions so as to understand how the patient came to need to be on the operating table, and how this might have been prevented. All the best special- ists practise a holistic art, and our aim is to show how specialism and holism may be successfully interwoven, if not into a fully watertight garment, then at least into one which keeps out much of the criticism rained upon us by the proponents of alternative medicine.

We hope that by compiling this little volume we may make the arduous task of learning medicine a little less exhausting, so allowing more energy to be spent at the bedside, and on the wards. For a medical student coming fresh to a specialty the great tomes which mark the road to knowledge can numb the mind after a while, and what started out fresh is in danger of becoming exhausted by its own too much. It is not that we are against the great tomes themselves—we are simply against reading them too much and too soon. One starts off strong on ‘care’ and weak on knowledge, and the danger is that this state of aff airs becomes reversed. It is easier to learn from books than from patients, yet what our patients teach us may be of more abiding signifi cance:

the value of sympathy, the uses of compassion and the limits of our human world. It is at the bedside that we learn how to be of practical help to peo- ple who are numbed by the mysterious disasters of womb or tomb, for which they are totally unprepared. If this small book enables those starting to ex- plore the major specialties to learn all they can from their patients, it will have served its purpose—and can then be discarded.

Because of the page-a-subject format, the balance of topics in the follow- ing pages may at fi rst strike the reader as being odd in places. However, it has been our intention to provide a maximally useful text rather than one which is perfectly balanced in apportioning space according to how common a particular topic is—just as the great Terrestrial Globes made by George Phil- lips in the 1960s may seem at fi rst to provide an odd balance of place names, with Alice Springs appearing more prominently than Amsterdam. To chart a whole continent, and omit to name a single central location out of respect for

‘balance’ is to miss a good opportunity to be useful. George Phillips did not miss this opportunity, and neither we hope, have we. It is inevitable that some readers will be disappointed that we have left out their favoured subjects (the Phillips’ Globe does not even mention Oxford!). To these readers we off er over 300 blank pages by way of apology.

JABC&JML—Preface to the 1^st edition—Ferring, 1987

Confl icts of interest: none declared

Because of numerous and well-publicized occasions where writers of guide- lines recommending certain drugs turn out to have undisclosed fi nancial contacts with the pharmaceutical industries concerned,1 we wish to place on record that we have no contacts with any pharmaceutical company, and no pharmaceutical company employs us in any capacity, and neither have we re- ceived any fi nancial input bearing upon our research for this publication. We have a policy of not seeing representatives from the pharmaceutical industry, or receiving their gifts or hospitality. We assert that the drugs recommended in this book have been selected on the basis of the best available evidence.

DRs LONGMORE, COLLIER, and AMARAKONE, 2012

vi

Understanding our patients

Most of the time we treat our patients quite well, without ever really under- standing them. The idea that we should strive to understand and empathize with all our patients is unreasonable. Out-patient clinics and surgeries would grind to a halt, and urgent visits would never get done. It is also possible that to do so would be counter-productive from the patient’s point of view. For two human beings to understand each other’s inner life is a rare event, and if we off ered this understanding to all our patients they might become addict- ed to us, and be unable to get on with the rest of their lives. Nevertheless, it is good practice to try to understand some patients. Doing so may entail swal- lowing an alien world and digesting it rather slowly. Paradoxically, to achieve this, we very often need to keep our mouths shut, particularly with those in whom we have reached a therapeutic impasse—for example if the illness is untreatable, or the patient has rejected our treatment, or if the patient seems to be asking or appealing for something more. Eye contact is important here.

One of the authors (JML) recalls forever his very fi rst patient—found on a sur- gical ward recovering from the repair of a perforated duodenal ulcer: a nice simple surgical patient, ideal for beginners. I asked all the questions in the book, and knew all his answers and his physical features, even the colour of his eyes. Luckily, the house offi cer who was really looking after him did not ask so many questions, and knew how to interpret the appeal for help behind those eyes, and in his busy day found space to receive the vital clue beyond my grasp—that my patient was a drug addict and under great stress as he could no longer fi nance his activity.

So, the fi rst step in trying to understand a patient is to sit back and listen.

Next, if possible, it is very helpful to see your patient often, to establish rap- port and mutual respect. If the relationship is all one way, with the doctor fi nding out all about the patient, but revealing nothing of him or herself, this mutual respect can take a very long time to grow. But beware of sharing too much of your own inner life with your patients: you may overburden them, or put them off . Diff erent patients respond to diff erent approaches. Understand- ing patients inevitably takes time, and it may be hard in a series of short ap- pointments. A visit to the patient’s home may be very revealing, but for many doctors trapped in hospital wards or clinics, this is impossible. But it is usual- ly possible to have a longish private interview, and take whatever opportunity arises. We once worked with a consultant who infuriated his junior staff on busy ward rounds by repeatedly selecting what seemed to us the most bor- ing and commonplace medical ‘cases’ (such as someone with a stroke) and proceeding to draw the curtain around the patient’s bed to exclude us, and engage in what seemed like a long chat with the patient, all in very hushed voices, so that we never knew what he said—until Sister told us that he never said anything much, and simply received anything that was on the pa- tient’s mind. For the most part, he was swallowing their world in silence. We came to realize that there was nothing that these patients, robbed as they were of health and wholeness, appreciated more in their entire hospital stay.

vii

What happens when two ward rounds collide?

We once worked with a splendid consultant, Dr B—, who, among other ec- centric but lovable traits, believed that data such as an ECG should be inter- preted according to the mood of the day and in the light of bedside nuances.

He would not let us label old ECGs with the diagnosis accorded at the time of their recording, in case this confl icted with later nuances. So during ward rounds old ECGs would be unearthed and reinterpreted by the great man, as if he were a conductor wringing new meaning from a well-known score.

Ward rounds tended to be rather slow and it so happened that faster, newer consultants would start overtaking us on ward rounds. But we noticed that some of their entourage would take this moment of impact to hive off from the fast ward round, and attach themselves to ours. The faster ward round moved on to some trite destination leaving us to tussle with the great ques- tions of medicine.

Let us consider further this moment of instability and choice when the two ward rounds collide. As Paul Verlaine wrote, “There is nothing more precious than a song which is cloudy from the joining of the indistinct with the precise”.

We tend to over-value the precise and undervalue the indistinct. Like Dr B—, we need to re-interpret patients’ exact words as if they were a musical score. All too often, though, we rely on summaries of our patients’ stories, massacred by eloquent, but treacherous, medical jargon. Paul Verlaine knew what to do: “Take eloquence, and wring its neck” is his advice, if it’s truth we are after. In its place he recommends systematic ambiguity and giving nuance free rein....

C

ar nous voulons la Nuance encor, For we want nuance, Pas la couleur, rien que la Nuance! Not colour, nothing but nuance!

Oh! la nuance seule fi ance Only nuance joins

Le rêve au rêve et la fl ûte au cor! Dream to dream and fl utes to horns!

Paul Verlaine, Art poétique

So what are the facts? Give me hard facts and I will give you a diagnosis.

That was the alluring but dangerous message from the fast ward round. And we all have to make our choice of when to hive off from this ward round and join Dr B—. If we can accord some ambiguity to the facts we may start to be of real use to our patients. After all, they have to live with the facts, so we may as well let the facts breathe and have a complicated life of their own.

There is something undefi ned in every fact. Find what it is, and use the undefi ned as a vehicle to explore your patient’s subtleties and contradictions.

So, in memory of Dr B—, we propose a new section in the Medical Notes called Nuances, to be placed before the Functional Enquiry and after the History of the Presenting Complaint. “The patient pointed to his ear when he said this” or “He was obviously frightened reliving this moment...” or “The patient ran out of language at this point...”

Running out of language is a sure sign that you are getting somewhere with our patient. Too much eloquence is fatal: this is Paul Verlaine’s worthless jewel (“ce bijou d’un sou”) that sounds hollow and fake when put to the test.

We have to accept that language is not very good at dealing with pain—or any internal state.

viii

Dedication

ix

Acknowledgements

We thank those who have contributed their time and wisdom to previous edi- tions: Dr Steven Emmet for detailed help in reading proofs; Professor Tor Chiu for his help with the ENT chapter; Natalie Langdown for help with autism; Pro- fessor Mark Lowenthal for his indefatigable help with Paediatrics and other chapters. We thank all the authors who have joined us for previous editions: Ju- dith Harvey, Tim Hodgetts, Duncan Brown, Peter Scally, Mark Brinsden, Ahmad R. Mafi , and Tom Turmezei.

Specialist Readers We are hugely indebted to our Specialist Readers for their advice, encouragement, and constructive criticism. Each chapter in this book has benefi tted from their trustworthy oversight. They are thanked individually at the beginning of each chapter.

Junior Readers It was our great pleasure to welcome a new team of Read- ers to the ninth edition of this book. Our Junior Readers showed commitment, intelligence, and ingenuity in their contributions to the referencing and cross- referencing of this edition. We have a better book for it. Thank you to Mathura- nayagham Niroshan, Shahzad Arain, Rashmi Singh, Josh Hurn, Konstantinos Kritikos, Mark Cassar, William Hunt, David Lee, Aaron Lai, Winnie Chen, Yong De Jun, Pooja Sarkar, Xuebin Dong, Roland Bensted, and Fandy Wang.

Reader participation We have been very fortunate to receive so many well- considered suggestions and corrections to the book from readers . Their con- tributions have enhanced the book and we are grateful. Over the years the list has grown too large to accommodate in the book, so we now have a dedicated webpage for the purpose: www.oup.com/uk/ohcs9acknowledgements.

If you would like to give us feedback, correct a mistake, or make a suggestion, you can do so by fi lling in the comment card enclosed in this volume and posting it to us, or by going to our website: www.oup.com/uk/ohcs9efeedback.

x

How to use this book

This book has some useful features to help you get the most out of the informa- tion inside.

Quick chapter look-ups Index on the back cover refers to and aligns with the coloured tabs on the sides of the pages.

References (1) Every reference has an individual identifi cation indicated by a pink superscript number. The full details of every reference are held online at www.oup.com/ohcs9refs.

Cross references There are cross references to other chapters within the book, to the Oxford Handbook of Clinical Medicine (OHCM), and to other titles in the Oxford Medical Handbooks series.

Reference intervals Included inside the back cover. Conversion factors to and from SI units are given on the bookmark.

Right-hand vertical comments At the side of some tables and topics, an alter- native opinion of the content inside.

Symbols and abbreviations See opposite.

Corrections and suggestions Found a mistake? Have a suggestion for the next edition? Let us know at www.oup.com/uk/ohcs9efeedback. Major changes are announced online at www.oup.co.uk/academic/series/oxhmed/updates.

A note on the use of pronouns

For brevity, the pronoun ‘he’ or ‘she’ has been used in places where ‘he or she’

would have been appropriate. Such circumlocutions do not aid the reader in forming a vivid visual impression, which is one of the leading aims of good au- thorship. Therefore, for balance and fairness, and where sense allows, we have tried alternating he with she.

 ...don’t dawdle! Prompt action saves lives

...this phrase is important

more (or less) vital topic; a rough

 ⁽ † ⁾

guide for 1^st-time readers



...an opportunity for holistic/non-

reductionist thinking ...confl ict (controversial topic)

1^,2^,3 ...references at oup.co.uk/ohcs9refs

1^,2^,3 ...drug dose not in BNF, see

oup.co.uk/ohcs9refs

# ...fracture

 ...diff erential diagnosis

 :  ...male to female ratio

 ...decreased

 ...normal (eg plasma level)

 ...increased

~ ...about

≈ ...approximately equal –ve ...negative +ve ...positive

...on account of/because of

...therefore

A&E ...emergency department

A2A ...angiotensin 2 receptor (blockers)

ABC ...air, breathing, circulation

A(P)LS ..advanced (paediatric) life support

manuals

ABR ...audiological brainstem responses

AC ...ante cibum (before food)

ACE(i) ...angiotensin-converting enzyme (inhibitor)

ACLS ...advanced cardiac life support

ACTH ...adrenocorticotrophic hormone

ADD ...attention defi cit disorder

ADH ...antidiuretic hormone

AFP ...-fetoprotein (^=alpha)

AIDS ...acquired immunodefi ciency syn.

Alk ...alkaline (phos=phosphatase)

ALL ...acute lymphoblastic leukaemia

ALT...alanine aminotransferase

ANA ...antinuclear antibody

ANF ...antinuclear factor

ANS...autonomic nervous system

AP ...anteroposterior

APH...antepartum haemorrhage

APLS ...advanced paediatric life support

APM ...auto-premotor syndrome

ARF ...acute renal failure

ARM...artifi cial rupture of membranes

ASD ...atrioseptal defect

ASO ...antistreptolysin O (titre)

ASW ...approved social worker

ATLS ...Advanced Trauma Life Support

manual; see www.trauma.org

ATN ...acute tubular necrosis

AV ...atrioventricular

AVM ...arteriovenous malformation

^{HCG ...}-human chorionic gonadotrophin

BJGP ...British Journal of General Practice

BMJ ...British Medical Journal

BNA ...borderline nuclear abnormality

BNF ...British National Formulary

BNF^C...children’s BNF

BP...blood pressure

© ...courtesy of the copyright holder

C3 ...complement

Ca ...carcinoma

CBRN ....chemical, biological, radiological,

nuclear

CBT ...cognitive-behaviour therapy

CCDC ....consultant in communicable

disease control

CCF ...combined (right & left sided)

cardiac failure

CHC ...combined hormonal

contraception

ChVS ...chorionic villus sampling

CI ...contraindications

CIN ...cervical intra-epithelial neoplasia

CMV ...cytomegalovirus; controlled

mandatory ventilation

CNS ...central nervous system

CoC ...combined oral contraceptive

COM ...chronic otitis media

CPA ...care programme approach

CPAP ...continuous +ve airways pressure

CPR ...cardiopulmonary resuscitation

CRP ...c-reactive protein

CRPS ...complex regional pain syndrome

CSF ...cerebrospinal fl uid

CT ...computer tomography

CVP ...central venous pressure

CVS ...cardiovascular system

CXR ...chest x-ray

D ...dimension (or dioptre)

D&C...dilatation (cervix) & curettage D&V ...diarrhoea and vomiting dB ...decibel

DHS ...dynamic hip screw

DIC ...disseminated intravascular

coagulation

DIP ...distal interphalangeal

DKA ...diabetic ketoacidosis

dL ...decilitre

DM ...diabetes mellitus

DMSA ...dimercaptosuccinic acid

DNA ...deoxyribonucleic acid

DOH...Department of Health (NHS)

DPL ...diagnostic peritoneal lavage

DRG ...dorsal root ganglion

DSM-IV Diagnostic & Statistical Manual, 4^e

DUB ...dysfunctional uterine bleeding

DVT ...deep venous thrombosis

E-BM ....evidence-based medicine

EBV ...Epstein–Barr virus

ECG ...electrocardiogram

ECT ...electroconvulsive therapy

EEG ...electroencephalogram

EIA ...enzyme immunoassay

ENT ...ear, nose and throat

ERPC ...evacuation of retained products

of conception

ESR ...erythrocyte sedimentation rate

ET ...endotracheal

FB ...foreign body

FBC ...full blood count

FCR ...fl exor carpi radialis

FDP ...fl exor digitorum profundus

FDS ...fl exor digitorum sublimis

FH ...family history

FNA ...fi ne needle aspiration

Symbols and abbreviations

xi xi

xi xi

xii

FNT ...fetal nuchal translucency

FSH ...follicle-stimulating hormone

G ...gauge g ...gram

G()^GT .gamma()glutamyl trans-

peptidase

G6PD ....glucose-6-phosphate

dehydrogenase

GA ...general anaesthesia

GCS ...Glasgow coma scale

GFR ...glomerular fi ltration rate

GH ...growth hormone

GI ...gastrointestinal

GP ...general practitioner

h ...hour

Hb ...haemoglobin

HBsAg ..hepatitis B surface antigen

HBV ...hepatitis B virus

HCG ...human chorionic gonadotrophin

HDL ...high-density lipoprotein

HFOV...high-frequency oscillatory

ventilation

HIV...human immunodefi ciency virus

HLA ...human leucocyte alleles

HPA ...Health Protection Agency

HPO ...hypothalamic–pituitary–ovarian

HPV ...human papilloma virus

HRT ...hormone replacement therapy

HVS ...high vaginal swab

ibid ...ibidem (Latin, in the same place)

IBW ...ideal body weight

ICP ...intracranial pressure

IE ...infective endocarditis

Ig ...immunoglobulin

IHD...ischaemic heart disease

IM ...intramuscular

INR...international normalized ratio of

prothrombin time

IOP ...intraocular pressure

IP ...interphalangeal

IPPV ...intermittent positive pressure

ventilation

IPT ...interpersonal therapy

IQ ...intelligence quotient

ISQ ...in status quo (Latin, no change)

ISS ...injury severity score

ITP ...idiopathic thrombocytopenic

purpura

ITU ...intensive therapy unit

IU/iu ...international unit

IUCD ...intrauterine contraceptive device

IUI...intrauterine insemination

IV ...intravenous

IVF ...in vitro fertilization

IVI...intravenous infusion

IVU...intravenous urography

JVP ...jugular venous pressure

K⁺ ...potassium

kg ...kilogram kpa ...kilopascal L ...litre

LA...local anaesthesia

LBC ...liquid-based cytology

LCR ...ligase chain reaction

LDH ...lactate dehydrogenase

LFT ...liver function test

LH ...luteinizing hormone

LHRH ....luteinizing hormone-releasing

hormone

LMP ...day 1 of last menstrual period

LMWH ..low molecular weight heparin

LP ...lumbar puncture

LVH ...left ventricular hypertrophy

μ(g) ...micro(gram)

MAOI ....monoamine oxidase inhibitor

MCP ...metacarpophalangeal

MCV ...mean cell volume

MEA ...microwave endometrial ablation

MET ...meta-analysis

mg ...milligrams (μg=microgram=mcg)

MHA ...Mental Health Act

MI ...myocardial infarction

ML ...millilitre

mmHg millimetres of mercury

MRI ...magnetic resonance imaging

MSU ...midstream urine culture

MTP ...metatarsophalangeal

mU...milliunit(s)

MVA ...motor vehicle accident

N=20* ...reference to a randomized trial of 20 patients (* or what ever number follows N) n=63* ...reference to a non-randomized

trial of 63 patients (* or what ever number follows n)

N2O ...nitrous oxide

NaCl ...sodium chloride

NAI ...non-accidental injury

NBM ...nil by mouth (no solids or fl uids)

NEJM ....New England Journal of Medicine

NEPE ...non-epileptic paroxysmal events

NGT ...nasogastric tube

NHS ...National Health Service

NICE ...National Institute for Health and

Clinical Excellence

NICU ...neonatal intensive care unit

NMJ ...neuromuscular junction

NOF ...neck of femur

NSAID ..non-steroidal anti-infl ammatory drug(s)

OAE ...otoacoustic emissions

OED ...Oxford English Dictionary, OUP

OHCM ...Oxford Handbook of Clinical

Medicine 8^e, OUP

OM ...otitis media

OME ...otitis media with eff usion

OMV ...open mouth view

ON ...omni nocte (take at night)

ORh–ve .blood group O, Rh negative

ORIF ...open reduction and internal fi xation

OT ...occupational therapist

PA ...posteroanterior

PaCO2 ...partial pressure of CO2 in arterial

blood

PAN ...polyarteritis nodosa

pANCA .perinuclear antineutrophil cytoplasmic antibody

PaO2 ...partial pressure of oxygen in

arterial blood

PC ...post cibum (after food)

PCA ...patient-controlled anaesthesia

PCOS...polycystic ovarian syndrome

PCR ...polymerase chain reaction

PCV ...packed cell volume

xi

xi xi

xi xi

xi

xiii

PDA ...patent ductus arteriosus

PE ...pulmonary embolus

PET ...pre-eclamptic toxaemia

PG ...pemphigoid gestations

PGD...preimplantation genetic diagnosis

PICU ...paediatric intensive care unit

PID ...pelvic infl ammatory disease

PIP ...proximal interphalangeal

PKU ...phenylketonuria

PMB ...postmenopausal bleeding

PMS ...premenstrual syndrome

PO ...per os (Latin for by mouth)

PoP...progesterone-only pill

POP ...plaster of Paris

PPH ...postpartum haemorrhage

PR...per rectum

PTR ...prothrombin ratio

PUO ...pyrexia of unknown origin

PUVA ....psoralen-ultraviolet A

PV ...per vaginam (via the vagina)

QOF ...quality & outcomes framework

 ...treatment (prescribing drugs)

RA ...rheumatoid arthritis; regional

anaesthesia

RBC ...red blood cell

RCGP ....Royal College of General

Practitioners

RCOG ....Royal College of Obstetricians

and Gynaecologists

RCT ...randomized controlled trial

REM ...rapid eye movement

RMO ...registered medical offi cer

RSD ...refl ex sympathetic dystrophy

RSI ...repetitive strain injury; rapid

sequence induction

RTA ...road traffi c accident(s)

RTS ...revised trauma score

RUQ ...right upper quadrant

RVH ...right ventricular hypertrophy

S1 S2 ...1^st and 2^nd heart sounds

SAD ...seasonal aff ective disorder

SALT ...speech and language therapist

SAO2 ...arterial blood O2 saturation, ≈ SpO2

(allows for carboxyhaemoglobin)

SBE ...subacute bacterial endocarditis

SC ...subcutaneous

SCBU ....special care baby unit

SE ...side-eff ects

sec...second(s)

SFH ...symphysis fundal height

SERM ....selective oestrogen receptor

modulator

SGA ...small-for-gestational age

SLE...systemic lupus erythematosus

SNHL ....sensorineural hearing loss

SpO2 ...pulse oximetry estimated

SaO2; no allowance for carboxyhaemoglobin

SSRI ...selective serotonin reuptake

inhibitor(s)

stat ...statim (Latin for once); single dose

STD ...sexually transmitted disease

STI ...Sexually transmitted infection

SUFE ...slipped upper femoral epiphysis

SVC ...superior vena cava

SVP ...saturation vapour pressure

syn ...syndrome

T° ...temperature, degrees Centigrade

t½ ...half life

T3 ...triiodothyronine

T4 ...thyroxine

TB...tuberculosis

TBW ...tension band wiring

TCRE ...transcervical resection of

endometrium

TED ...transverse elastic graduated

TENS...transcutaneous electrical nerve

stimulation

TFT...thyroid function tests

TIA ...transient ischaemic attack

ToP ...termination of pregnancy

TPH ...transplacental haemorrhage

TPR ...temperature, pulse, and

respirations

TRTS ...triage revised trauma score

TSH ...thyroid-stimulating hormone

TSOH ....transient synovitis of the hip

U ...unit(s)

U&E ...urea and electrolytes

UK ...United Kingdom

URTI ...upper respiratory tract infection

US(S) ...ultrasound (scan)

UTI ...urinary tract infection

UV ...ultraviolet

VLBW ...very low birthweight infant

VSD ...ventriculoseptal defect

VTE ...venous thromboembolism

VUR ...vesico-ureteric refl ux

WCC ...white blood cell count

wt ...weight

WR ...Wasserman reaction

yrs, y....years

ZN ...Ziehl–Neelsen (stain for TB)

Fig 1. This plan is rendered almost unintelligible by over-use of abbreviations. It might mean:

If in status quo (ISQ=no change in state) in 2 days’ time (/7 in this context means days; /52 would mean weeks), refer to the Sexually Transmitted Infections clinic for treatment (^)—

if it turns out he does not arrive (DNA), follow-up at the out-patient department.2 xi

xi xi

xi xi

1 Obstetrics

Pre-pregnancy counselling 2 Hypertension & eclampsia¹48

Care plans 3 Prematurity 50

Booking criteria 4 Small for gestational age 52 Physiological changes in Large for gestational age 53

pregnancy 6 Postmaturity 54

Obesity 7 ^Fetal distress 55

Antenatal care 8 Obstetric shock 55

Anti-D 9 Antepartum haemorrhage 56

Prenatal diagnosis 10 Normal labour 58

Tests for Down’s syndrome 12 Membrane rupture 60

Preimplatation tests 13 Induction of labour 62

Placenta 14 Active management of labour 64

Thromboprophylaxis 16 Pain relief in labour 66 Minor symptoms 17 Multiple pregnancy, IVF68–9 Hyperemesis gravidarum 18 Breech 70

Pregnancy & medical conditions Other malpresentations 71 – Sickle-cell disease 19 ^Prolapsed cord 72 – Cardiac disease 20 Impacted shoulders 72 – Psychopharmacology 21 Meconium-stained liquor 73

– Anaemia 22 Dystocia 74

– HIV 23 Forceps/ventouse 76

– Diabetes mellitus 24 Caesarean section 78 – Thyroid disease 25 Uterine rupture 80 – Jaundice 26 Mendelson’s syndrome 80

– Malaria 27 Stillbirth 82

– Renal disease 28 Postpartum haemorrhage 84 – Epilepsy 29 Retained placenta 86 – Connective tissue disease 30 ^Uterine inversion 86 – Hypertension 31 DIC and coagulation defects 88 – Thromboembolism 32 Amniotic fl uid embolism 89 – Thrombophilia 33 Birth injuries 90,

Ante/perinatal infection 34–7 maternal 91

Abdominal pain 38 Episiotomy and tears 92

Abdominal palpation 40 Puerperium 94

Pelvis and head 42 Contraception after a baby 95 Fetal monitoring 44–5 Maternal mortality 96

Ultrasound 46 Perinatal mortality 97

Sources RCOG Green Top guidelines; Saving Mothers’ Lives (Confi dential En- quiry). 1 ^Matmort2011 Cochrane database (www.liv.ac.uk/lstm/ehcap/pc/nwc-pcl.html).

Relevant topics elsewhere: Neonatology, p107–22; breastfeeding, p124–6; rhe- sus disease, p116; ectopic pregnancy, p262; miscarriage/termination, p258–60;

trophoblastic disease, p264; fi broids in pregnancy, p277; preterm/light-for- dates babies, p128; chickenpox in pregnancy, p144; parvo virus B19, p142; post- natal depression, p408.

1 The term pregnancy-induced hypertension with proteinuria is tending to replace the term pre- eclampsia. We have not followed this trend as to do so obscures the vital fact about pre- eclampsia: it may lead on to eclampsia. We favour pre-eclampsia because it is short and sends the shadow of a shiver down our spines, being a reminder of how dangerous it can be.

We thank Ms Alison Peattie, our Specialist Reader, and Mathuranayagham Niroshan, our Junior Reader, for their contribution to this chapter.

Obs te trics



The essence of reproductive health 1

Pregnancy is a risky aff air for babies and mothers. The textbook causes of maternal mortality in the UK are pulmonary embolism, eclampsia, haemor- rhage, infection, and cardiac diseases, with all the other causes being rare.

But if an obstetrician could be granted one wish, it would not be to abol- ish these; rather it would be to make every pregnancy planned and desired by the mother. Worldwide, a woman dies every minute from the eff ects of pregnancy, and most of these women never wanted to be pregnant in the fi rst place—but either had no means of contraception, or were without the skills, authority, and self-confi dence to negotiate with their partners. So the real killers are poverty, ignorance, and the unwieldy desires of men, and the real solutions entail literacy, economic growth, and an equality of dialogue between the sexes. Any obstetric or governmental initiatives in reproductive health which do not recognize these facts are doomed. 2

School-based sex education This can be eff ective, if linked to easy access to contraceptive services. This is the conclusion of a meta-analysis, taking into account cohort studies (if meta-analyses confi ne themselves to the 15 or so randomized studies, no benefi t is shown). 3 It may be necessary to foster a knowledge-sharing, skill-promoting environment that is part of a continuing process, and not a ‘one-off ’ aff air—for educational programmes to work. Adolescent pregnancy rates: USA: 116/1000; UK: 57/1000; Canada:

50/1000. In 2007 in England & Wales 160 pregnancy were terminated in those <14 years old (out of ~200,000 terminations and ~650,000 live births). 4

Defi nitions

Gravidity refers to the number of pregnancies that a woman has had (to any stage). Parity refers to pregnancies that resulted in delivery beyond 28 weeks’ gestation. An example of the shorthand way of expressing pregnancies before and after 28 weeks is: para 2+1. This means that she has had 2 pregnancies beyond 28 completed weeks’ gestation, and 1 which terminated prior to 28 weeks. If she is not pregnant at the time of describing her she is gravida 3, but if she is pregnant now she is gravida 4. Twins present a problem as there is controversy as to whether they count as 1 for both parity and gravidity or should count as 2 for parity.

It is unclear whether the cut-off point in these defi nitions should now be 24 weeks, to harmonize with the new defi nition of stillbirth (p82). In general, aim to use proper English rather than the shorthand described above, which is open to ambiguity. For example, when presenting a patient try something like: ‘Mrs Cottard is a 32-year-old lady who is 15 weeks into her 4^th pregnancy;

the 3^rd ended in a miscarriage at 17 weeks, and the others came to term with normal deliveries of children who are now 2 & 8.’ The bald statement ‘Para 2+1’

is ambiguous, incomprehensible to the patient, and misses the point that the patient is now approaching the time when she lost her last baby.

Length of pregnancy: Normal pregnancy is 40 weeks from the LMP. Nae- gele’s rule: expected delivery date (EDD) ≈ 1yr and 7 days after LMP minus 3 months (not if last period was a withdrawal bleed; for cycles shorter than 28 days, subtract the diff erence from 28; if longer, add the diff erence). A revised rule suggests the addition of 10 days rather than 7 is more accurate.

Obst etrics

2

Pre-pregnancy counselling

The aim is to help prospective parents embark upon pregnancy under conditions most likely to ensure optimal fetal and maternal wellbeing. Babies conceived 18–23 months after a live birth have lowest rate of perinatal problems.5 Reduce weight if obese (for risks of obesity see p7). Ensure the woman is rubella (± chickenpox, p144) immune prior to pregnancy; assess need for thromboprophylaxis in pregnancy (p16). Other areas include:

•Optimal control of chronic disease (eg diabetes) before conception. This is also important for hypothyroidism as the fetus cannot make thyroxine until 12 weeks and under-replacement may aff ect neurodevelopment. Strict diet is essential peri-conceptually for women with phenylketonuria (PKU).

•Stop teratogens or seek expert advice prior to conception (p29, p31). Parox- etine is associated with fetal heart defects in 1^st trimester use, as is lithium (rate  8 : 1000 to 60 : 1000) with Ebstein’s anomaly  from 1 to 10 per 20 000.6

HIV drugs didanosine and efavirenz have teratogenic potential and avoidance may be possible 7 in fi rst trimester (seek expert advice).

•Medication to protect the fetus from abnormality (eg folate supplements for neural tube defects, see p140 and below).

•Provide expert information for those at  risk of abnormality so pregnancy or its avoidance is an informed choice, and any tests needed (eg chorionic villus sampling, p10) are planned. Regional genetic services give detailed pre- pregnancy counselling. See p154. In relevant ethnic populations, take blood for thalassaemia and sickle-cell tests (p22). If ‘cut’ (p247) off er defi bulation.

•Avoidance of infection: eg sperm washing advised if HIV+ve male partner and HIV-ve woman

•If past/family history of thromboembolism, screen for thrombophilia.

Diet To prevent neural tube defects (NTD) and cleft lip, all should have folate- rich foods + folic acid 0.4mg daily>1 month pre-conception till 13wks (5mg/day if past NTD, on anti epileptics, p29, obese (BMI≥30), ^HIV+ve on co-trimoxazole prophylaxis, 8 diabetic 9 or sickle cell disease p19).Foods with >0.1mg of folic acid/serving: brussels sprouts, asparagus, spinach, blackeye beans, fortifi ed cereals. Avoid liver & vit. A (vit. A embryopathy) & caff eine.

Smoking decreases ovulations, causes abnormal sperm production (± less penetrating capacity),  rates of miscarriage (≈2), and is associated with preterm labour and lighter-for-dates babies (mean

is 3376g in non-smoker; smoker: 3200g), placenta praevia and abruption.10 Reduced reading ability in smokers’ children up to 11yrs old shows that long- term eff ects are important. ~17% of smoking moth- ers stop before or in pregnancy.

Alcohol consumption High levels of consump- tion are known to cause the fetal alcohol syndrome (p138). Mild drinking eg 1–2U/wk has not been shown to adversely aff ect the fetus but alcohol does cross the placenta and may aff ect the fetal brain. Miscar- riage rates are higher among drinkers of alcohol. NICE

recommends <1U/24h. Binge drinking (>5U/session) is especially harmful.11 To cut consumption: see p513.

Spontaneous miscarriage (SM) Risk of miscarriage is 8.9% in women aged 20–40yrs, rising to 74.7% for women ≥45yrs. After 3 miscarriages, risk of next preg- nancy failure is 44.6% for nullips aged 25–29yrs, and 35.4% for parous women. 12

Recurrent spontaneous miscarriage See p261.

Search for those who need counselling most

•Diabetes mellitus

•Tropical travellers

•Frequent miscarriage

•Hypothyroidism

•Epilepsy

•Rubella-susceptible

•Pet-owners (toxo- plasmosis risk is )

•Phenylketonuria

•BP

•SLE

•Genetic history, eg:

•spina bifi da etc.

•thalassemia

•Duchenne’s

•cystic fi brosis ^{et al}

†

3

Obs te trics

Individualized care plans—eg for diabetes mellitus9

For optimal care, when there are many features that need to be addressed an individualized care plan can help. The example below is of a care plan for diabetic women. The care plan is a chance for dialogue between the mother and her carers: all must sign-up to it. Placed in her notes it should be consulted throughout pregnancy when the woman is seen. In the case of a diabetic pregnancy the woman should be seen in a joint clinic where a multidisciplinary team is available comprising obstetrician, diabetes physician, diabetic specialist nurse, diabetes midwife, and dietician.

The care plan should cover the antenatal period and up to 6 weeks post-partum. It can be individualized, and generally includes advice about:

•Aspirin 75mg/24h PO until delivery to reduce pre-eclampsia risk.13

•Targets for glycaemic control (p24 for levels; pregnant mother to liaise every 2 weeks with diabetic team concerning blood readings).

•Retinal digital screening with mydriasis schedule (as soon as possible after pregnancy confi rmed if not screened in previous 12 months; after 1^st ante- natal appointment and again at 16–20 weeks if retinopathy seen on initial screen in pregnancy and at 28 weeks if none seen at initial screening). 14 Up to 20% develop proliferative retinopathy.

•Renal screening schedule (for microalbuminuria as well as dipstix protein, at 1^st appointment if not screened in previous 12 months). Refer to nephrologist if creatinine ≥120μmol/L or protein excretion >2g/day. Give thromboprophylaxis if protein excretion >5g/day.

•Fetal surveillance (eg 4 chamber and outfl ow tract echo at 20 weeks;

ultrasounds at 28, 32, and 36 weeks for fetal growth and amniotic fl uid depth and cardiotocogram eg twice weekly from 38 weeks if she chooses to await spontaneous labour rather than accepting induction/caesarean sec- tion when off ered at 38 weeks) earlier if growth restriction seen.

•Plan for delivery. If co-morbidity such as neuropathy or obesity arrange anaesthetic assessment at 36 weeks.

•Diabetes care after delivery.

If macrosomia is found on ultrasound the consultant obstetrician should then write a clear plan to determine follow-up scans, fetal surveillance, and mode and time of delivery.

For postnatal care the care plan should include, as a minimum:

•Plan for managing glycaemic control (eg return to pre-pregnancy regimen).

•Neonatal care: feed as soon as possible then 2–3hrly to prevent hypoglycae- mia. Check glucose level at 2–4h after birth, and if signs of hypoglycaemia.

Give IV glucose to baby if symptomatically hypoglycaemic. Tube feed or give

IV glucose if 2 consecutive readings <2mmol/L despite maximal feeding or if unable to feed. Do not discharge to community until >24h old, feeding well and able to maintain glucose levels.

•Contraception (currently mothers with the worst obstetric outcomes are the least likely to receive contraceptive advice).

•Follow-up care after discharge from hospital (eg glucose tolerance test 6 weeks postpartum and annually to see if still diabetic in gestational dia- betes).

•How to access pre-pregnancy review prior to subsequent pregnancies.



The advantage of care plans is that by documenting the plan, it ena- bles members of the team (including the mother and father, for they are frequently the most reliable at making sure things happen if they know what is expected) to check that pregnancy is monitored as planned.

4

Obst etrics

Booking criteria and home delivery

Most women in the UK have ‘shared obstetric care’—ie most of their antenatal care is from the community midwife (±^GP), with limited (or no) visits (usually 2) to the hospital to see the consultant under whose care they are delivered, returning home (eg after 6–72h) for postnatal care. A minority receive their complete care from hospitals and the usual reasons for this are that the compli- cations envisaged make full consultant care desirable. Some women are cared for by community midwives and their GP, but increasingly, low-risk women are receiving all their care from midwives, with doctors involved only if complica- tions arise. Delivery may be in hospital in consultant- or midwife-led units, or, more rarely, at home. There is quite good evidence that consultant input into antenatal care of normal pregnancies achieves no added benefi ts (p8)—but risk factors making specialist visits and booking desirable are generally agreed (see

MINIBOX).

Is it safe for low-risk mothers to deliver in high- technology hospitals? Here interventions with their complications are more common. In the UK this question is usually academic (unless a midwife-led delivery unit is available) as most GPs are reluctant to conduct births—and 6 months’ training in obstet- rics gives scant skill. The rising birth rate and service pressures are putting these big hospitals under great strain. In places (eg New Zealand, Holland) where delivery outside of big hospitals is the norm, there is fairly clear (but not uncontested ) evidence that on all measures, and in all but the highest risk groups, big hospitals come out less favourably. The few trials seeming to favour high-technology are now recog- nized to be seriously fl awed.

Home delivery (Rare in England: 2.8% of births in 2007 at home, 2% in freestanding midwifery units, 3% in alongside midwifery units.) Data comparing morbidity and mortality in home vs hospital delivery is sparse but a 2008–10 (N=65,438) study showed in- creased morbidity and high rate of transfer in labour for nullips. 15 But an important observation is that rapid intervention is necessary to save life (maternal or fetal) in ~5% of low-risk pregnancies. This pin- points the need for any domiciliary service to have good equipment available for home delivery and good emergency back-up (eg by emergency obstetric am- bulance units—ie specially trained ambulance per- sonnel who, it is hoped, will liaise directly with senior medical obstetric staff in hospital).

Birth centres off er homely birth in congenial sur- roundings (eg with purpose-designed birthing pools). Formerly, labour ward facilities were nearby,

if needed, and the mother was attended by her GP and community midwife. A randomized trial showed that mothers’ satisfaction is great, and nearly all re- quested this type of delivery for future births. 16 Such centres may off er a com- promise to adherents of home delivery, and go a long way towards celebrating rather than medicalizing birth. But we note that new UK birth centres may be en- tirely run by midwives, so if an obstetrician is needed (or an epidural) a lengthy and possibly risky journey is needed. 17www.birthchoiceuk.com.

Risk factor—vis à vis:

The mother

•>40yrs old

•Nullip <20 or >34yrs

•History of infertility

• ≥5 past pregnancies

•Multip <154cm tall

•Primip <158cm tall

•Obese with BMI≥³⁵

•Social deprivation

•HBSAg or HIV+ve p34 Past deliveries

•Preterm or small (<37 weeks, <2.5kg)

•Deformity, still-birth, or neonatal death

•Caesarean section

•Hysterotomy

•Retained placenta/PPH

•Placental abruption

•Had pelvic fl oor repair

•Instrumental deliveries

•Poor fetal growth or wellbeing

•Diabetes,  ^BP, anaemia

•Malpresentations after 34 weeks

•Serum -fetoprotein  This pregnancy

•Cardiac/thyroid disease

•Renal/liver disease

•Multiple pregnancy

•Rh antibodies (p116)

•Autoimmune disorders

•Asthma/epilepsy

5

Obs te trics

Issues surrounding home delivery¹ 5

Remember that normal delivery is a retrospective diagnosis.

•In the UK, because of past hospital experience of many abnormal labours,

GPs are often very wary of home birth.

•Medico-legal aspects tend to dominate thoughts about worst-case scenarios—so that few GPs willingly take on intrapartum care.

•It’s not clear who is to do the doctor’s ordinary work when absent on a home delivery, if a mother particularly wants their GP present. Some small surgeries have had to close during delivery as no locum was available—an unacceptable consequence of off ering mothers extra choice. NB: in the UK, midwives, but not GPs, have a statutory duty to help at home deliveries.

•It is not clear if there are enough doctors or midwives with the necessary experience in suturing and neonatal resuscitation. Where there is a good team, there is no doubt that home delivery can be a safe and rewarding experience.

•Decisions about the place of labour are dynamic, and need revising (eg in 29%) as events in pregnancy unfold.

•Necessary equipment is not readily available, eg Entonox.®

•The key factor in increasing choice about home delivery is a good working relationship between the parents, the GP, and the midwife. Where this ex- ists, ~70% of home delivery requests tend to come to fruition; where the

GP is rated as being unsupportive, in a UK context, this fi gure drops to 54%.

•Everyone needs to know that transfer in labour is common in labours start- ing off as planned home deliveries (9–14% if multip, 36–45% if primip)—

and there is excess morbidity for primips, though levels are still low. 18

•It is salutary to note that <20% of pregnancies in England and Wales are considered ‘normal’ and without antenatal or postnatal complications. 19 If normal delivery is defi ned as delivery without use of general anaesthetic, induction, epidural, instrumentation or surgical intervention, the normal delivery rate in England in 2003 was 51%. 20 In the 2008–2010 study it was 58% for planned obstetric unit birth, 76% alongside midwifery unit, 83%

freestanding midwifery unit and 88% for home birth. 18 However, over- medicalization is a real problem too, eg in ≥20% of labours (p58).

•Intrapartum perinatal mortality rate for intended home delivery (1994–

2003) was 0.48 : 1000 births for intended home delivery, 1.42 : 1000 for un- intended home delivery, and 6.05 : 1000 births for women transferred to another place for delivery. 21 Average intrapartum mortality for England and Wales for all births for this period was 0.79 : 1000 births.

Indications for intrapartum transfer

•Malpresentation or breech in labour

•Signifi cant meconium-stained liquor

•Fetal heart monitoring indication including heart rate abnormalities (p44)

•Delay in 1^st or 2^nd stage labour

•Epidural pain relief requested

•Maternal T^o >38, or twice T^o >37.5, 2h apart

•Retained placenta (p86)

•Maternal BP raised +140/ and/or +/90

•Uncertainty if fetal heart heard

•Emergency: (ante/post-partum haemorrhage, cord presentation/prolapse, maternal collapse or need for advanced neonatal resuscitation)

•3^rd or 4^th degree vaginal tear or other complicated perineal repair needed.

When considering transfer bear in mind imminence of birth.

6

Obst etrics

Physiological changes in pregnancy

Hormonal changes Progesterone, synthesized by the corpus luteum until 35 post-conception days and by the placenta mainly thereafter, decreases smooth muscle excitability (uterus, gut, ureters) and raises body temperature.

Oestrogens (90% oestriol) increase breast and nipple growth, water reten- tion, and protein synthesis. The maternal thyroid often enlarges due to in- creased colloid production. Thyroxine levels, see p25. Pituitary secretion of prolactin rises throughout pregnancy. Maternal cortisol output is increased but unbound levels remain constant.

Genital changes The 100g non-pregnant uterus weighs 1100g by term. Mus- cle hypertrophy occurs up to 20 weeks, with stretching after that. The cervix may develop ectropion (‘erosions’). Late in pregnancy cervical collagen reduc- es. Vaginal discharge increases due to cervical ectopy, cell desquamation, and

 mucus production from a vasocongested vagina.

Haemodynamic changes Blood: From 10 weeks the plasma volume rises un- til 32 weeks when it is 3.8 litres (50% >non-pregnant). Red cell volume rises from 1.4 litres when non-pregnant to 1.64 litres at term if iron supplements not taken (18%), or 1.8 litres at term ( 30%) if supplements are taken—hence Hb falls due to dilution (physiological ‘anaemia’). WCC (mean 10.5 ≈ 10⁹/L), plate- lets, ESR (up 4-fold), cholesterol, -globulin, and fi brinogen are raised. Albumin and gamma-globulin fall. Urea and creatinine fall.

Cardiovascular: Cardiac output rises from 5 litres/min to 6.5–7 litres/min in the fi rst 10 weeks by increasing stroke volume (10%) and pulse rate (by ~15 beats/min). Peripheral resistance falls (due to hormonal changes). BP, particu- larly diastolic, falls during the second trimester by 10–20mmHg, then rises to non-pregnant levels by term. With increased venous distensibility, and raised venous pressure (as occurs with any pelvic mass), varicose veins may form.

Vasodilatation and hypotension stimulate renin and angiotensin release—an important feature of BP regulation in pregnancy.

Aorto-caval compression From 20 weeks the gravid uterus compresses the inferior vena cava (and to a lesser extent the aorta) in supine women reducing venous return. This reduces cardiac output by 30–40% (so-called supine hypo- tension). Placing the woman in left lateral position or wedging her tilting 15°

to the left relieves the pressure and restores cardiac output.

Other changes Ventilation increases 40% (tidal volume rises from 500 to 700mL), the increased depth of breath being a progesterone eff ect. O2 con- sumption increases only 20%. Breathlessness is common as maternal PaCO2 is set lower to allow the fetus to offl oad CO2. Gut motility is reduced, resulting in constipation, delayed gastric emptying, and, with a lax cardiac sphincter, heartburn. Renal size increases by ~1cm in length during pregnancy.

Frequency of micturition emerges early (glomerular fi ltration rate  by 60%), later from bladder pressure by the fetal head. The bladder muscle is lax but residual urine after micturition is not normally present. Skin pigmentation (eg in linea nigra, nipples, or as chloasma—brown patches of pigmentation seen especially on the face), palmar erythema, spider naevi, and striae are common.

Hair shedding from the head is reduced in pregnancy but the extra hairs are shed in the puerperium.

Pregnancy tests Positive eg from 9 days post-conception (or from day 23 of a 28-day cycle) until ~20 weeks of pregnancy; they remain positive for ~5 days after miscarriage or fetal death. Otherwise, the false +ve rate is low. They detect the -subunit of human chorionic gonadotrophin in early morning urine, so are positive in trophoblastic disease (p264).

†

7

Obs te trics

Maternal obesity aff ects the fetus adversely, casting a long fat shadow over the baby’s adult life (with risk of heart disease, diabetes, the met- abolic syndrome and some cancers, eg breast, lung). 23 Epigenetic mechanisms (p653) mean that the over- (and under)nutrition may infl uence not just this baby, but subsequent generations down the centuries. 24 There is also risk of macrosomia, meconium aspiration. 25 Incidence is rising in the

UK and women with a BMI >35 constitute 15% of mothers dying, and almost 50% of those dying from thromboembolism are obese.

As mothers may be more motivated to accept lifestyle modifi cations, pregnancy is a period during which obesity can be more eff ectively man- aged. Control of body weight during this period is vital. Aim to encour- age weight loss well before embarking on planned pregnancy. NB: dieting during pregnancy may not be wise as low weight gain during pregnancy correlates with lighter babies more prone to postnatal problems. 26 Good evidence is lacking. Lowest neonatal mortality is for birth weights of 3500–4500g and maternal weight gain depending on BMI: 27

BMI<19.8 recommended total weight gain (not twins): 12.5–18kg

19.8–26 11.5–16kg

26.1–29.0 7–11.5kg

>29 2*–6kg

*Assuming personal coaching and using a food diary (“I didn’t eat the cake as I knew I’d have to write it down, so I chose fruit instead...”). Some may need no weight gain. medicinenet.com/script/main/art.asp?articlekey=100897

2010 CMACE/RCOG guidelines recommend giving 5mg folic acid from 1 month before conception and for the fi rst trimester if BMI≥30 to prevent increased risk of neural tube defects. Obese women are more prone to vitamin D defi ciency so ensure they are taking 10μg vitamin ^D supplemen- tation while pregnant and breastfeeding. If BMI≥30, screen for diabetes, eg oral glucose tolerance test at 24–28 weeks and consider heparin throm- boprophylaxis for 7 days postnatally if one additional thrombotic risk fac- tor (p16), with addition of TED stockings if 2 risk factors. Mobilize all obese women early. If women with BMI≥30 require caesarean section, give ^IV prophylactic antibiotics and, if subcutaneous fat is >2cm thick, suture that separately, to prevent infection.

Women with BMI≥40 should always receive 7-day postnatal heparin prophylaxis and TED stockings whatever the mode of delivery. They should have an antenatal consultation with an obstetric anaesthetist with an an- aesthetic plan made for labour and delivery, and need 3^rd trimester assess- ment to plan manual handling requirements and provision of appropriate

TED stockings. When in labour inform anaesthetist. They should have con- tinuous midwifery care and should have an IV sited early in labour. If opera- tive delivery is required the attending anaesthetic should be a consultant (or signed off obese-competent) obstetric anaesthetist.

Pregnancy and obesity 22 (^BMI >30 at booking, p530)

"Eating for 2 is the only nice thing about being pregnant"

For mothers, obesity in- creases prevalence of:

•Miscarriage

•Pre-eclampsia

•Gestational diabetes

•Thromboembolism

•Cardiac disease

•Induced labour

•Caesarean section

•Infection (eg post-op)

•PPH

•Maternal mortality

•Feeding by bottle