Antenatal Care

1
Antenatal Care
Continuing Medical Education Activities for
Non-specialists Dr TC Pun 27/2/2002
2
Antenatal Care

• Introduction
• The first visit
• Subsequent visits
• Screening tests
• Prenatal diagnosis and ultrasonogram
• General advice
• Summary

3
Introduction

• Objectives
• education and information
• screening
• early identification of complications
• treatment of complications

4
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 20014CD000934

5
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

6
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
• Cochrane Database Syst Rev 20014CD000934

7
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)
• Cochrane Database Syst Rev 20014CD000934

8
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)
• Cochrane Database Syst Rev 20014CD000934

9
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
  induced hypertension improved
• number of NST, hospital admission, duration of
  stay reduced
• Chan FY et al 1993 Asia-Oceania J Obstet
  Gynaecol 19(3)291-298

10
Antenatal Care

• Introduction
• The first visit
• Subsequent visits
• Screening tests
• Prenatal diagnosis and ultrasonogram
• General advice
• Summary

11
The first visit

• timing
• history
• physical examination
• risk determination

12
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

13

• Guidance on Ultrasound Procedures in Early
  Pregnancy
• Royal College of Radiologists, Royal College of
  Obstetricians and Gynaecologists 1995

14
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 the ovaries, the presence of any
  ovarian cyst or any findings suggestive of an
  ectopic pregnancy

15
Miscarriage

• Silent miscarriage
• sac diameter gt20 mm with no evidence of embryo or
  yolk sac
• CRL gt6 mm with no evidence of cardiac pulsation
• if sac diameter lt20 mm or CRL lt 6 mm, repeat at
  least 1 week later

16
Miscarriage

• Incomplete miscarriage
• thick irregular echoes in the midline of the
  uterine cavity
• differential diagnosis blood clots

17
Miscarriage

• Complete miscarriage
• well defined regular endometrial line
• reliability 98

18
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

19
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

20
The first visit

• Early Pregnancy Assessment Unit
• Streamline the management of women with early
  pregnancy bleeding or pain
• Reduce the admission time

21
The first visit

• timing
• history
• physical examination
• risk determination

22
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
• ODonovan et al 1988 Br J Obstet Gynaecol
  95556-9

23
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 the
  past 3 years
• Lancet 1988432-3

24
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 6819-23)
• cytological diagnostic pitfalls unique to this
  population(Michael Esfahani 1997 Diagn
  Cytopatho 1799-107)

25
The first visit

• timing
• history
• physical examination
• risk determination

26
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

27
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

28
The first visit

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

29
Modified McGill Score(1)

• Demographic
• age lt16(1)
• parity gt5(1)
• weight lt38 kg(1)
• weight gt70 kg(1)
• unstable family(2)

30
Modified McGill Score(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)

31
Modified McGill Score(3)

• Habits
• smoking(1)
• alcohol(1)
• drug addiction(2)
• Growth
• discrepancy gt2 weeks(2)

32
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)

33
Modified McGill Score(5)

• Current pregnancy
• recurrent vaginal bleeding gt 12 weeks(2)
• anaemia lt10 g(1), lt9 g(2)
• hypertension(2)
• hydramnios(2)
• oligohydramnios(2)
• multiple pregnancy(2)
• Rh negative mother(2)

34
Antenatal Care

• Introduction
• The first visit
• Subsequent visits
• Screening tests
• Prenatal diagnosis and ultrasonogram
• General advice
• Summary

35
Subsequent visits

• Patterns of routine antenatal care for low-risk
  pregnancy
• 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
• Cochrane Database Syst Rev 20014CD000934

36
Subsequent visits

• Patterns of routine antenatal care for low-risk
  pregnancy
• 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.
• Cochrane Database Syst Rev 20014CD000934

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38
Subsequent visits

• every 4 week till 28 weeks
• every 2 week till 36 weeks
• every week till delivery

39
Subsequent visits

• Fundal height for IUGR
• high specificity
• moderate sensitivity
• high negative predictive value
• only one randomized trial unwise to
  abandon(Cochrane Database Syst Rev.
  2000(2)CD000944)

40
Antenatal Care

• Introduction
• The first visit
• Subsequent visits
• Screening tests
• Prenatal diagnosis and ultrasonogram
• General advice
• Summary

41
Screening tests

• Hb at booking and at 30-32 weeks
• Rh for isoimmunisation
• rubella immune status
• VDRL
• HbsAg status
• cervical smear
• MCV

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44
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

45
Screening tests

• HIV
• information to be given
• mother to baby transmission occurs in 15-40 and
  treatment can reduce the chance
• window period
• confidentiality

46
Screening tests

• Results of the first 3 months
• 10238 tests were performed
• 4 chose not to be tested
• 6 positive results

47
Screening tests

• Biochemical screening for Downs 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)

48
Screening tests

• Biochemical screening for Downs Syndrome
• value of addition of oestriol controversial
• role of nuchal lucency measurement

49
Screening tests

• Gestational diabetes
• increase in perinatal mortality associated with
  abnormal 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

50
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

51
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

52
Screening tests

• Other screening tests
• Group B streptococcus
• Bacterial vaginosis

53
Antenatal Care

• Introduction
• The first visit
• Subsequent visits
• Screening tests
• Prenatal diagnosis and ultrasonogram
• General advice
• Summary

54
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

55
Prenatal diagnosis and ultrasonogram

• 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

56
Prenatal diagnosis and ultrasonogram

• Possible merits of USG
• placenta localisation
• sex of child
• others some chromosome disorders, fetal death,
  ectopic pregnancy, molar pregnancy

57
Prenatal diagnosis and ultrasonogram

• 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
  handedness

58
Antenatal Care

• Introduction
• The first visit
• Subsequent visits
• Screening tests
• Prenatal diagnosis and ultrasonogram
• General advice
• Summary

59
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)

60
General advice

• 236 ml of milk contains
• 146.3 kcal
• 7.3 g protein
• Ca 259.6 mg

61
General advice

• Iron and folate supplement
• clear evidence of an improvement in
  haematological 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)

62
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)

63
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)

64
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
  33209-13)

65
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)

66
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

67
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

68
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)

69
General advice

• Coffee
• when used in moderation, no association with
  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

70
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)

71
http//www.cemd.org.uk/reports/c14.pdf
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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)

73
http//www.emsvillage.com/village_library/article2
.cfm?id9
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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)

75
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)

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General advice

• Warning 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)

77
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)

78
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)

79
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)

80
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

81
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

82
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

83
Summary(4)

• usual exercise and work should not be affected
• commercial cord blood collection and stem-cell
  storage should not be recommended

84
Thank You!
Dr TC Pun Tsan Yuk Hospital Hong Kong