Antenatal Care

Antenatal Care

Continuing Medical Education Activities for Non-specialists

Dr TC Pun

27/2/2002

Antenatal Care

• Introduction

• The first visit

• Subsequent visits

• Screening tests

• Prenatal diagnosis and ultrasonogram

• General advice

• Summary

Introduction

Objectives

• education and information

• screening

• early identification of complications

• treatment of complications

Introduction

Patterns of routine antenatal care for low-risk pregnancy

• assess the effects of antenatal care programmes for low-risk women

• three trials, all conducted in developed countries, evaluating the type of care provider

Cochrane Database Syst Rev 2001;4:CD000934

Introduction

• Giles 1992 – midwives versus obstetricians, 89 women, cost savings

• Tucker 1996 – general practitioners and midwives versus shared care, 1765 women, clinical effectiveness and satisfaction

• Turnbull 1996 – midwives versus shared care, 1299 women, clinical effectiveness and satisfaction

Introduction

• no difference for several outcome variables including caesarean section, anaemia, urinary tract infections and postpartum haemorrhage

• there is a trend to lower rate of preterm delivery, antepartum haemorrhage, lower perinatal mortality

• lack of recognition of fetal malpresentations tended to be higher in this group


Introduction

• the midwife/general practitioner managed care group had a statistically significant lower rate of pregnancy induced hypertension and pre-eclampsia

• overall, it appears that satisfaction with midwife/general practitioner managed care was similar or higher (in some variables)


Introduction

Shared antenatal care between Family Health Services and Hospital(Consultant) Services for Low Risk Women

• decrease in workload to hospital clinics• diagnosis of IUGR, malpresentation, pregnancy in

duced hypertension improved• number of NST, hospital admission, duration of st

ay reduced

Chan FY et al 1993 Asia-Oceania J Obstet Gynaecol 19(3):291-298

Antenatal Care

• Introduction

• The first visit


• Screening tests


• General advice

• Summary

The first visit

• timing

• history

• physical examination

• risk determination

The first visit

Timing

• pregnancy test positive within a few days after missed period

• early pregnancy complications like miscarriages, ectopic pregnancy may be first diagnosed in the clinic

Guidance on Ultrasound Procedures in Early Pregnancy

Royal College of Radiologists, Royal College of Obstetricians and Gynaecologists 1995

What should be reported

• number of sacs and mean gestation sac diameter• regularity and outline of the sac• presence of any haematoma• presence of a yolk sac• presence of a fetal pole• CRL• presence/absence of fetal heart movement• extrauterine observations should include the appearance of t

he ovaries, the presence of any ovarian cyst or any findings suggestive of an ectopic pregnancy

Miscarriage

Silent miscarriage

• sac diameter >20 mm with no evidence of embryo or yolk sac

• CRL >6 mm with no evidence of cardiac pulsation

• if sac diameter <20 mm or CRL < 6 mm, repeat at least 1 week later

Miscarriage

Incomplete miscarriage

• thick irregular echoes in the midline of the uterine cavity

• differential diagnosis: blood clots

Miscarriage

Complete miscarriage

• well defined regular endometrial line

• reliability: 98%

Ectopic pregnancy

• live embryo within a gestational sac in the adnexa - gold standard

• poorly defined tubal ring

• presence of varying amount of fluid in the Pouch of Douglas

Ectopic pregnancy

• may be normal in up to a quarter of patients• enlarged but empty uterus with or without an

adnexal mass and/or fluid in the Pouch of Douglas

• early diagnosis of normal intrauterine pregnancy in transvaginal scan

• complex adnexal mass seen in 7% of patients with normal intrauterine pregnancies

The first visit

Early Pregnancy Assessment Unit

• Streamline the management of women with early pregnancy bleeding or pain

• Reduce the admission time

The first visit

• timing

• history



The first visit

Is routine antenatal booking vaginal examination necessary for reasons other than cervical cytology if ultrasound examination is planned?

• 11622 consecutive case records abstracted retrospectively

• If ultrasound is planned has few advantages beyond the taking of a cervical smear

O’Donovan et al 1988 Br J Obstet Gynaecol 95:556-9

The first visit

Routine vaginal examination at antenatal booking

• reasonable to reserve VE at the booking antenatal clinic for women– with a clinical indication, such as pain, bleeding

or vaginitis– who have not had a satisfactory smear within th

e past 3 yearsLancet 1988:

432-3

The first visit

Pitfalls associated with cervical screening during pregnancy

• sampling difficulty because of enlargement of cervix, increased mucous secretion and increased difficulty in viewing the cervix(Cronje et al 2000 Int J Gynecol Obstet 68:19-23)

• cytological diagnostic pitfalls unique to this population(Michael & Esfahani 1997 Diagn Cytopatho 17:99-107)

The first visit

• timing

• history



The first visit

Risk scoring system

• difficult to make quantitative estimates of the exact risk associated with a given factor

• validity of adding weighed scores

• difficulty in definition of risk factors

• more predictive of outcome in second or late pregnancies

The first visit

Risk scoring system• both the positive(10-30%) and negative

predictive values of all scoring systems are poor

• risk of increase in intervention• may help to provide a minimum level of

care and attention in settings where these are inadequate

The first visit

Modified McGill’s score• with score 2 and above will be seen at TYH• Demographic• Obstetrical history• Habits• Growth• Medical problems• Current pregnancy

Modified McGill Score(1)

Demographic

• age <16(1)

• parity >5(1)

• weight <38 kg(1)

• weight >70 kg(1)

• unstable family(2)


Obstetric History• perinatal death(2)• SGA/LBW baby(2)• gestational proteinuric hypertension(2)• abruptio placentae(2)• previous caesarean section(1)• infertility(1)• IGT/GDM(1)


Habits

• smoking(1)

• alcohol(1)

• drug addiction(2)

Growth

• discrepancy >2 weeks(2)

Modified McGill Score(4)Medical problems• recurrent UTI(2)• impaired renal function(2)• heart disease(2)• essential hypertension(2)• severe respiratory disease(2)• diabetes mellitus(2)• hyperthyroidism(2)• jaundice(2)• other major disease(2)


Current pregnancy• recurrent vaginal bleeding > 12 weeks(2)• anaemia <10 g(1), <9 g(2)• hypertension(2)• hydramnios(2)• oligohydramnios(2)• multiple pregnancy(2)• Rh negative mother(2)

Antenatal Care

• Introduction

• The first visit


• Screening tests


• General advice

• Summary

Subsequent visits


• in developed countries with well established obstetrics services, small reductions in the number of prenatal visits (equal or less than two visits) are compatible with similar good perinatal outcomes

• women may be somehow disappointed with fewer visits


Subsequent visits


• in developing countries, in which a proportionally major reduction in the number of visits was achieved, also supports this conclusion

• in the light of the available evidence, the four antenatal care visits schedule tested in the largest trials appears to be the minimum that should be offered to low risk pregnant women.


40 week TY H

M CHC

36 week TY H

M CHC

30 week TY H

M CHC

Risk score 0 to 1

TY H till delivery

Risk score >1

First visit(booking)TY H or M CHC

Subsequent visits

• every 4 week till 28 weeks

• every 2 week till 36 weeks

• every week till delivery

Subsequent visits

Fundal height for IUGR

• high specificity

• moderate sensitivity

• high negative predictive value• only one randomized trial – ‘unwise to aban

don’(Cochrane Database Syst Rev. 2000;(2):CD000944)

Antenatal Care

• Introduction

• The first visit


• Screening tests


• General advice

• Summary

Screening tests

• Hb – at booking and at 30-32 weeks

• Rh – for isoimmunisation

• rubella immune status

• VDRL

• HbsAg status

• cervical smear

• MCV

no action

>80 fl

cause of maternalmicrocytosis

Paternal M CV>80 fl

Fe and Hb study

Paternal M CV<= 80 fl

husband calledback for M CV

<= 80 fl

M aternal M CVat booking

Fe therapyrepeat Fe later

Fedeficiency

thalassaemia

normalFe

Fe and Hb study

Screening tests

HIV

• opt-out screening since 1/9/2001

• information to be given– HIV is the virus causing AIDS but HIV

infection may not lead to AIDS till years later– positive result means infection; although there

is no cure but treatment can delay the onset of AIDS

Screening tests

HIV

• information to be given– mother to baby transmission occurs in 15-40%

and treatment can reduce the chance– window period– confidentiality

Screening tests

Results of the first 3 months

• 10238 tests were performed

• 4% chose not to be tested

• 6 positive results

Screening tests

Biochemical screening for Down’s Syndrome• 97% of Down syndrome pregnancies are

sporadic• age as screening test is not sensitive• AFP and HCG for screening between 15-20

weeks improves the sensitivity(screen positive rate of 5% or less, sensitivity of 60-70%)

Screening tests

Biochemical screening for Down’s Syndrome

• value of addition of oestriol controversial

• role of nuchal lucency measurement

Screening tests

Gestational diabetes• increase in perinatal mortality associated with abn

ormal glucose tolerance appears to be predicted as much by the indication for glucose tolerance testing

• no convincing evidence that treatment of women with an abnormal glucose tolerance test will reduce perinatal mortality or morbidity

• no benefit has been established for glucose screening

Screening tests

Gestational glucose tolerance screening at TYH

• 75 g OGTT for those with risk factors

• spot glucose screening using cut off of more than 5 mmol/l(more than) or 5.8 mmol/l(less than 2 hours after meal) for those without risk factors

Screening tests

Urine culture

• reduce the risk of pyelonephritis if followed by single dose therapy

• if culture not available, can be screened by a urine dipstick multiple test for leucocyte esterase and nitrite

Screening tests

Other screening tests

• Group B streptococcus

• Bacterial vaginosis

• ……

Antenatal Care

• Introduction

• The first visit


• Screening tests


• General advice

• Summary

Prenatal diagnosis and ultrasonogram

Referral to Prenatal Diagnosis and Counselling Department

• advanced maternal age• hereditary disease• maternal exposure to teratogen• previous abnormal children• abnormal screening test• suspected fetal abnormality


Possible merits of USG

• confirmation of the term date if performed before 24 weeks

• assessment of term date when history is unreliable

• detection of malformation

• detection of multiple pregnancy


Possible merits of USG

• placenta localisation

• sex of child

• others: some chromosome disorders, fetal death, ectopic pregnancy, molar pregnancy


• screening does not improve the outcome of pregnancy in terms of live births and morbidity

• reduced incidence of induction of labour for apparent post-term pregnancy

• twin pregnancies are detected earlier• no clear evidence of harm ?increase in left h

andedness

Antenatal Care

• Introduction

• The first visit


• Screening tests


• General advice

• Summary

General advice

Major difference of RDA in pregnancy

• Calorie 150 kcal more in first trimester, 350 kcal more subsequently

• Protein 60g (44 g in non-pregnant)

• Folate 400 ug (180 ug in non-pregnant)

• Calcium 1200 mg (800 mg in non-pregnant)

• Iron 30 mg (15 mg in non-pregnant)

General advice

236 ml of milk contains

• 146.3 kcal

• 7.3 g protein

• Ca 259.6 mg

General advice

Iron and folate supplement• clear evidence of an improvement in haematologic

al indices in women receiving routine iron and folate supplementation in pregnancy

• no conclusions can be drawn in terms of any effects, beneficial or harmful, on clinical outcomes for mother and baby as available data are often from single small trials

(Cochrane Database Syst Rev 2002 Issue 1)

General advice

Iron and folate supplement

• at present, there is no evidence to advise against a policy of routine iron and folate supplementation in pregnancy

• routine iron and folate supplementation could be warranted in populations in which iron and folate deficiency is common.

(Cochrane Database Syst Rev 2002 Issue 1)

General advice

Incidence of anaemia

• 1990-1992 7.5% of patients with anaemia

• 54.8% had thalassaemia

• 42.6% classified as iron deficiency

(Lao & Pun 1996 Eur J OG Reprod Bio 68: 53-8)

General advice

Effect of folate supplement on pregnant women with beta-thalassaemia minor

• Patients who received 5 mg folate daily showed a significant increase in predelivery Hb concentration

• Does not influence obstetric performance(Leung et al 1989 Eur J OG Reprod Bio 33:209-13)

General advice

Smoking

• 5-15 minutes Office based intervention increased cessation by 30-70%

• use of nicotine replacement products or other pharmaceuticals as smoking cessation aids during pregnancy has not been sufficiently evaluated

(ACOG Education Bulletin #260)

General advice

Alcohol

• known teratogen

• heavy maternal use is related to fetal alcohol syndrome

• moderate use may be related to spontaneous abortions and to developmental and behavioural dysfunction in the infant

General advice

Alcohol• should limit to no more than 2 drinks daily(1

ounce or 30 ml of absolute alcohol) (Am Council on Science and Health)

• a drink- 12 ounces(350 ml) of regular beer (150 calories) 5 ounces(150 ml) of wine (100 calories) 1.5 ounces(45 ml) of 80-proof distilled spirits (100 calories)

• safest course is abstinence

General advice

Coffee

• amount of caffeine in commonly used beverages varies widely– caffeinated coffee (66-146 mg)– non-herbal tea(20-46 mg)– caffeinated soft drinks (47 mg)

General advice

Coffee• when used in moderation, no association wi

th congenital malformation, miscarriage, preterm birth and low birth weight has been proven

• high dose may be associated with miscarriage, difficulty in becoming pregnant and infertility

General advice

Seat belt

• above and below the bump, not over it

• three-point seat belts should be worn throughout

• if necessary, the seat should be adjusted(Why mothers die: a report on confidential enquiries into

maternal deaths in the UK 1997-1999)

http://www.cemd.org.uk/reports/c14.pdf

General advice

Air bag• potential concern: the proximity of the gravid

uterus to the deploying air bag creates an increased risk of fetal death

• benefits appear to outweigh risks in pregnant women

• further study be done(National Conference on Medical Indications for Air Bag Disconnection

1997)

http://www.emsvillage.com/village_library/article2.cfm?id=9

General advice

Air travel• can fly safely up to 36 weeks(ACOG Committee Opinion

2001 #264)

• prevention of deep vein thrombosis– general – isometric calf exercise, walking around, drink

water/juices/soft drinks, avoid alcohol and caffeine

– ?compression stockings if over 3 hours(RCOG Scientific Advisory Committee

2001 #1)

General advice

Exercise

• 30 minutes or more of moderate exercise a day should occur on most, if not all, days of the week

• pregnant women also can adopt this recommendation

(ACOG Committee Opinion 2002 #267)

General adviceWarning signs to terminate exercise while pregnant• vaginal bleeding• dyspnea prior to exertion• dizziness• headache• chest pain• muscle weakness• calf pain or swelling• preterm labour• decreased fetal movement• amniotic fluid leakage (ACOG Committee Opinion 2002 #267)

General advice

Exercise

• avoid motionless standing

• avoid sports with high potential for contact, risk of falling, abdominal trauma, scuba diving

• avoid supine position after first trimester (ACOG Committee Opinion 2002 #267)

General advice

Work• most jobs cause no increased hazard to the

mother or baby• should be warned that if any complications

arise she must be able to leave work easily• specific hazards – chemical, physical,

biological, others(Chamberlain & Morgan 2002 in ABC of Antenatal Care)

General advice

Umbilical cord blood banking• routine directed commercial cord blood collection

and stem-cell storage cannot be recommended because of insufficient scientific base to support such practice and the attendant logistic problems of collection

• collection of altruistic donations and directed donations for at risk families remain acceptable procedures

(RCOG Scientific Advisory Committee 2001 #2)

Summary(1)

• family physicians should be involved in the provision of antenatal care in low risk patients

• early pregnancy complications are more commonly seen in primary care settings

• vaginal examination is not necessarily an integral part of antenatal care

• fundal height is probably useful for detecting IUGR

Summary(2)

• MCV and HIV tests are integral part of antenatal screening test

• urine culture and biochemical screening can be considered

• routine USG is useful in confirming the gestational age and detecting multiple pregnancy

Summary(3)

• additional 1-2 servings of milk should cover the additional nutritional need of pregnancy

• routine prescription of iron and folate is a reasonable practice

• additional folate supplement in thalassaemic patients can reduce anaemia

• seat belt should be worn and air bag should not be deactivated

Summary(4)

• usual exercise and work should not be affected

• commercial cord blood collection and stem-cell storage should not be recommended

Thank You!

Dr TC Pun

Tsan Yuk Hospital

Hong Kong

Antenatal Care

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