Antenatal Care
Antenatal care is the systematic medical supervision and screening provided to a pregnant woman from conception to the onset of labor to optimize maternal and fetal health outcomes.
Antenatal care (產前檢查) is the systematic, longitudinal medical care provided to pregnant women from confirmation of pregnancy through to delivery. Its overarching goal is "Healthy mother and healthy baby" [1].
The three pillars of antenatal care are:
Antenatal care is one of the most important preventive health programmes in medicine. It reduces maternal mortality, perinatal mortality, and long-term childhood morbidity by identifying and managing complications before they become emergencies.
What a safe clinician must NOT miss
- Pre-eclampsia developing after 20 weeks (BP + proteinuria at every visit)
- Ectopic pregnancy / molar pregnancy at booking
- Rhesus-negative mother without anti-D prophylaxis
- Unscreened GDM leading to macrosomia / shoulder dystocia
- Undetected fetal growth restriction (IUGR)
- Vertical transmission of HBV, HIV, syphilis
- Thalassaemia major pregnancy (both parents carriers)
- Placenta praevia undetected before labour
Before memorising the details, understand these 10 foundational ideas:
- Antenatal care is a screening programme — most women are healthy; the system is designed to sift out the minority who need specialist intervention.
- Dating accuracy is paramount — every downstream decision (preterm vs. term, induction timing, screening test validity) depends on correct gestational age.
- Risk stratification determines the care model — low-risk women can have shared/primary care; high-risk women need exclusive hospital care.
- Screening ≠ Diagnosis — a positive screen (e.g. combined first-trimester screen for Down syndrome) requires confirmatory diagnostic testing (e.g. amniocentesis/CVS).
- Prevention starts before conception — folate supplementation, medication adjustment, vaccination, and chronic disease optimisation ideally happen pre-pregnancy.
- Vertical transmission of infections is preventable — HBV, HIV, syphilis, and rubella all have specific antenatal protocols.
- Gestational diabetes and hypertensive disorders are the two commonest medical complications — both have dedicated screening and management pathways.
- Fetal surveillance evolves with gestation — from dating scan → anomaly scan → growth scans → CTG/biophysical profile near term.
- Every visit has a minimum dataset — BP, urinalysis, symphysio-fundal height (SFH), fetal heart, and maternal wellbeing enquiry.
- Patient education and shared decision-making are integral — counselling about diet, exercise, danger signs, birth planning, and breastfeeding.
Relevant Physiology and Epidemiology
| System | Change | Clinical Relevance |
|---|---|---|
| CVS | ↑CO 30–50%, ↑plasma volume > ↑RBC → dilutional anaemia; ↓SVR; flow murmur in 80% by end of 1st trimester [3] | Normal murmur ≠ pathology; supine hypotension in 3rd trimester |
| Haem | Hypercoagulable state (↑fibrinogen, factors VII/VIII/X; ↓protein S) | ↑VTE risk, especially post-partum 6 weeks [4] |
| Renal | ↑GFR 50%, ↓creatinine, glycosuria threshold lowered | Dipstick glucose may be physiological; creatinine > 75 µmol/L is abnormal in pregnancy |
| Resp | ↑tidal volume, ↓FRC, mild respiratory alkalosis | Dyspnoea is common but must exclude PE/cardiomyopathy |
| Endocrine | hCG drives early pregnancy; HPL causes insulin resistance in 2nd/3rd trimester | Basis of GDM screening at 24–28 weeks |
| GI | Progesterone → ↓LES tone, ↓gut motility | Reflux, constipation common |
- Birth rate ~35,000–40,000 per year in HK (declining trend)
- Maternal mortality < 5/100,000 (comparable to developed nations)
- Caesarean section rate ~25–30% in public hospitals
- GDM prevalence ~15–20% (high due to ethnic predisposition)
- HBsAg carriage rate ~5–8% in HK Chinese women
Pre-Pregnancy Care and Counselling
Ideally, all women should present prior to conception to their GP [5]. This is the true starting point of antenatal care.
| Group | Specific Actions |
|---|---|
| All women | Risk assessment and screening, assessment of need for vaccination, folate supplementation, general advice to optimise maternal health, general counselling, ± assessment of fertility [5] |
| Women with medical disorders (DM, thyroid, SLE, RA, post-transplant) | As above + assess effect of medical disorder (and Tx) on pregnancy, assess effect of pregnancy on medical disorder, optimisation of control, readjustment of medications [5] |
| Women with other RFs for abnormal pregnancy (severe pre-eclampsia, preterm delivery, pregnancy loss, previous baby with abnormalities) | As above + discussion on reproductive options, planning of pregnancy, offer early prenatal diagnosis [5] |
| Maternal Factors | Fetal Factors |
|---|---|
| Pre-existing medical diseases (DM, thyroid, HT, renal, valvular/congenital heart, autoimmune) | Growth problems (IUGR, macrosomia) |
| Pregnancy complications (bleeding, infection, exposures, GDM, HT) | Anomalies: inherited or sporadic |
| Operative risks (e.g. anaesthetic difficulties) | Infection: perinatal |
| Psychosocial issues | Trauma: at birth |
- Folic acid supplementation: 0.4 mg/day (routine) → prevents neural tube defects [6][7]
- High-risk women (previous NTD, on anti-epileptics, diabetes): 5 mg/day
- Medication review:
- Warfarin: teratogenic (highest risk 6–12 weeks) [4] → switch to LMWH before conception
- ACE-i/ARBs: contraindicated → switch to labetalol/nifedipine/methyldopa
- Sodium valproate: major teratogen (NTD) → switch if possible [8]
- Statins, retinoids, methotrexate: stop pre-conception
- ATD: PTU preferred in 1st trimester, then switch to carbimazole [9]
- Vaccination:
- Rubella: check immunity; vaccinate if non-immune (live vaccine → avoid conception for 4 weeks after)
- Varicella: if non-immune
- HPV: complete series before pregnancy
- Chronic disease optimisation:
- Lifestyle counselling: [7]
- Smoking, alcohol, substance abuse: stop for BOTH parents
- No known safe level of alcohol
- Optimal diet, weight — both too heavy and too light associated with adverse fetal outcomes
- Intimate partner violence screening — women may not proactively volunteer → use structured checklists
Booking Visit (首次產前檢查)
Symptoms of pregnancy: [11]
- Secondary amenorrhoea
- Nausea/vomiting (commonly ≤6w–3m, due to hCG; ± hyperemesis gravidarum if severe)
- Increased urinary frequency (pressure of gravid uterus on bladder, diminishes ≤12w)
- Excessive lassitude/lethargy (disappears after 12w)
- Breast tenderness and heaviness (↑progesterone)
- Fetal movements: usually not noticed until 20w (primipara) or 18w (multipara) [11]
Urinary/serum hCG: detectable 6 days after ovulation, usually test +ve from 4 weeks [11]
Ultrasound landmarks: [11]
- Fetal sac: visible 4.5–5 weeks
- Yolk sac: 5–6 weeks to 10 weeks
- Fetal pole with cardiac activity: 5.5–6 weeks
Gestational age: defined as time from 1st day of LMP [11]
EDD = LMP + 280 days or LMP + 9 months + 7 days (Naegele's rule) [11]
- If cycle > 28 days, add (cycle length − 28 days)
| Method | Advantages | Disadvantages |
|---|---|---|
| LMP dating | Simple | Assumes regular 28-day cycle, ovulation at day 14, accurate recall [11] |
| Ultrasound dating (recommended for all, ideally 10–14w) | Accurate even with irregular cycles; also detects multiple pregnancy, soft markers, failed IUP [11] | Only accurate if < 20 weeks — variation in fetal sizes minimal before 20w; after 20w, genes/environment cause significant variability [11] |
| ART dating | Most precise | Fertilisation date + 266 days [11] |
Ultrasound measurements: [11]
- CRL (crown–rump length): before 13w+6d
- Head circumference (HC): 14–20 weeks
Exam Tip
If there is a discrepancy between LMP dating and US dating of > 5–7 days in the first trimester, use the US date. After 20 weeks, US cannot reliably change dates.
- Demographics: age, race
- HPC: symptoms of pregnancy, dating (LMP), prior AN care
- Past Obstetric History: all previous pregnancies including miscarriages and terminations
- Antenatal complications (pre-eclampsia, APH)
- Labour and delivery: gestational age, duration, mode, complications (prolonged labour, malpresentation)
- Puerperal: complications (PPD, PPH)
- Neonatal: birth weight, sex, current health, complications
- Past Gynaecological History: problems, procedures, menstrual regularity, last Pap smear
- PMH/PSH/Psychiatric history
- Family history
- Social history: smoking, drinking, substance abuse [7]
First antenatal visit:
- General: inspection, maternal height/weight/BMI, BP, urinalysis (protein/glucose) [3]
- Lymph nodes and thyroid [3]
- Oedema: feet, lower legs, sacral [3]
- CVS: auscultation (flow murmur in 80% at end of 1st trimester is physiological) [3]
- Respiratory: auscultation [3]
- Breast: palpation — note CA breast during pregnancy a/w ↑rate of progression [12]
- Abdominal exam: scars (esp. previous C/S) [12]
- ± Pelvic exam:
| Investigation | Purpose | Action if Abnormal |
|---|---|---|
| Hb | Anaemia screening (anaemia if < 10.5 g/dL) | Most commonly Fe deficiency → iron supplementation |
| MCV | < 80 fL → consider iron deficiency (Fe profile) and thalassaemia trait (test partner's MCV → Hb studies) | If both parents carry thal trait → genetic counselling, prenatal diagnosis |
| ABO/Rh grouping | Risk of HDN in Rh-negative mothers | Anti-D prophylaxis at 28w and after sensitising events |
| HBsAg | Vertical transmission risk | Maternal TDF if ↑viral count; neonatal HBIG ≤12 hours + HBV vaccine [2][10] |
| HIV Ab | Vertical transmission risk | Confirm with Western blot → maternal + neonatal HAART, C-section, no breastfeeding [12] |
| Rubella Ab | Immunity check | Advise basic infection control + vaccination after delivery (live vaccine — cannot give in pregnancy) [12] |
| VDRL | Syphilis screening | Confirm with FTA-Abs → treat with multiple dose IM penicillin [12] |
| Urine dipstick | Glucose, protein as baseline | Proteinuria → ? renal disease; glycosuria → ? pre-existing DM |
| MSU C/ST | Asymptomatic bacteriuria → prevent pyelonephritis | Not routinely done in HK [12] |
| Cervical smear | Opportunistic screening: offered if not having regular screening | No if already having regular screening; yes if not, or advise postnatal screening [13] |
Common Pitfall
Do NOT forget to check MCV and partner's MCV when it is low. Missing thalassaemia trait is a significant medicolegal risk in Hong Kong where α-thal and β-thal trait prevalence is ~8%.
Systems for antenatal care: [1]
- Exclusive hospital (specialist) care — public or private
- Primary health care based with referral to specialist only when indicated (MCHC, midwife-led clinic)
- Shared care between hospital and primary health care
QMH/TYH Obstetric Shared Care Programme [14]
- After booking, risk is evaluated by modified McGill score
- Score ≥ 2 → antenatal care in QMH (hospital-based)
- Score 0–1 → shared care (MCHC + hospital)
Examples of conditions mandating hospital care: [14]
- Obstetric history: perinatal death, SGA/LBW baby, pre-eclampsia, abruptio placentae (NOT GDM)
- Medical conditions: recurrent UTI, heart disease, other major diseases
- Current pregnancy: recurrent PVB > 12w, anaemia < 9 g, HT, multiple pregnancy, oligohydramnios, discrepancy in uterine size > 2 weeks
Schedule of Antenatal Visits
- Q4w from 0–28 weeks
- Q2–3w from 28–36 weeks
- Q1w from 36 weeks onwards
Now: tailored to attendance for screening tests, increased frequency if risk factors present [12]
| Gestation | Key Actions |
|---|---|
| Pre-pregnancy | Risk assessment, folate, medication adjustment, vaccination, lifestyle |
| 6–10 weeks | Confirmation of pregnancy (hCG, ± early US if indicated) |
| 10–14 weeks (Booking) | Full Hx, PE, booking bloods, dating US, NT scan/combined first-trimester screening for Down syndrome |
| 16 weeks | Review booking results; if thal trait → partner screening → consider prenatal diagnosis |
| 18–22 weeks | Anomaly scan (detailed structural survey) |
| 24–28 weeks | OGTT for GDM screening; Hb recheck; anti-D for Rh-negative women (28w) |
| 28–32 weeks | Growth assessment (SFH ± US); fetal movements counselling; start TDF for high-viral-load HBV mothers [2] |
| 32–34 weeks | Presentation check; growth; BP/proteinuria |
| 35–37 weeks | GBS screening (low vaginal + rectal swab) [10]; presentation; birth planning |
| 36–40 weeks | Weekly visits; SFH, BP, urinalysis; engagement of presenting part; discuss IOL if post-dates |
| 40+0 to 41+0 weeks | Discuss induction of labour; membrane sweep; fetal surveillance (CTG, AFI) |
Antenatal Screening and Investigations by Trimester
| Test | Timing | What It Screens For | Interpretation |
|---|---|---|---|
| Dating US (CRL) | 10–13+6w | Gestational age, viability, multiple pregnancy, chorionicity | CRL measurement plotted on charts |
| Nuchal translucency (NT) scan | 11–13+6w | Down syndrome (T21), T18, T13 | Combined with maternal age + serum markers (PAPP-A, free β-hCG) = combined first-trimester screening |
| Combined first-trimester screening | 11–13+6w | Fetal aneuploidies | Risk cut-off (e.g. > 1:250) → offer diagnostic test (CVS 11–14w or amniocentesis > 15w) |
| Booking bloods | 10–14w | As per booking investigation table above | See above |
Screening for fetal anomalies and Down syndrome: [1]
- Screening programme for specific abnormalities — screening for fetal Down syndrome, thalassaemia [1]
- The combined first-trimester screen has detection rate ~85–90% with 5% false positive rate
- Non-invasive prenatal testing (NIPT/cfDNA): available in HK, high sensitivity/specificity for T21 (> 99%), used as secondary screen or primary screen (patient-funded in public sector)
| Test | Timing | Purpose |
|---|---|---|
| Anomaly scan (morphology scan) | 18–22 weeks | Detailed structural survey of all fetal systems; soft markers for aneuploidies; placental localisation; cervical length |
| Quad test (if missed 1st trimester screen) | 15–20w | AFP, hCG, uE3, inhibin A → risk for T21 and NTD |
| OGTT | 24–28 weeks | GDM screening — 75g OGTT (WHO criteria) |
| Hb recheck | 28w | Detect anaemia that has developed since booking |
| Anti-D immunoglobulin | 28 weeks | For Rh-negative women to prevent sensitisation |
| Antibody screen | 28w | Detect new alloantibodies |
| Test | Timing | Purpose |
|---|---|---|
| SFH measurement | Every visit from 24–26w | Screen for IUGR and macrosomia; small SFH: consider IUGR, wrong dates, oligohydramnios, IUD, transverse lie; large SFH: wrong dates, polyhydramnios, multiple pregnancy, macrosomia [3] |
| Growth US | 28–36w (if indicated) | Biometry (BPD, HC, AC, FL), estimated fetal weight, AFI, Dopplers |
| GBS swab | 35–37 weeks [10] | Low vaginal + rectal swab (without speculum); if positive → intrapartum antibiotic prophylaxis (IAP) |
| Presentation check | 36w onwards | Confirm cephalic; if breech → offer ECV at 37w |
| CTG | ≥ 28w (if indicated); routine from 40w+ | Fetal heart rate pattern; reassuring vs. non-reassuring |
| HIV viral load | 36w (if HIV+) | Determines mode of delivery (if < 50 copies/mL → vaginal delivery can be supported) [10] |
| Parameter | Why |
|---|---|
| Blood pressure | Pre-existing HTN (< 20w), pre-eclampsia (> 20w) [3] |
| Urinalysis: protein | ≥ 2+ suggests pre-eclampsia [3] |
| Urinalysis: glucose | May suggest GDM [3] |
| Symphysio-fundal height (SFH) | From ~24w; plots on customised growth chart |
| Fetal heart auscultation | From ~14w by Doppler, ~28w by Pinard |
| Maternal wellbeing enquiry | Symptoms, fetal movements, psychosocial issues |
| Oedema | Peripheral vs. generalised (pre-eclampsia red flag if sudden onset/facial) |
| Maternal weight | At subsequent visits [3] |
SFH Measurement Technique and Interpretation [3]
- Palpate fundus with ulnar border of left hand
- Landmarks: palpable by 12w; umbilicus at 20w; xiphisternum at 36w (then may be stable or come down)
- Measure from top of pubic symphysis to fundus; use inch side of tape and turn over to read
- Interpretation: usually number of weeks in cm (from 20–36w); use charts (±3 cm in Chinese, ±2 cm in Caucasians) [3]
Specific Screening Programmes in Detail
- MCV < 80 fL at booking → check iron status (ferritin/Fe profile)
- If iron replete and MCV still low → suspect thal trait → Hb electrophoresis/HPLC
- Test partner's MCV [12]
- If both parents are carriers of the same type → genetic counselling → offer prenatal diagnosis (CVS/amniocentesis)
- α-thal: if both parents are α⁰ carriers (SEA deletion) → risk of Bart's hydrops fetalis (lethal)
- β-thal: risk of β-thal major → lifelong transfusion dependence
- All women: ABO/Rh typing at booking [12]
- Rh-negative women (~5% of Chinese women):
- Anti-D prophylaxis at 28 weeks (routine)
- Anti-D within 72 hours after any sensitising event (miscarriage, APH, amniocentesis, ECV, delivery of Rh+ baby)
- Indirect Coombs test (antibody screen) at booking and 28 weeks
- If antibodies detected → serial titres → if rising → referral for MCA Doppler (peak systolic velocity) to assess for fetal anaemia
| Infection | Test | Timing | Action if Positive |
|---|---|---|---|
| Hepatitis B | HBsAg | Booking | Neonatal HBIG ≤ 12h + HBV vaccine; maternal TDF if HBV DNA > 2×10⁵ IU/mL (start last trimester, stop 3 months post-delivery) [10][2] |
| HIV | HIV Ab | Booking | Confirm Western blot → maternal + neonatal HAART; C-section if VL > 50; avoid breastfeeding [10][12] |
| Syphilis | VDRL | Booking | Confirm FTA-Abs → multiple dose IM penicillin [12] |
| Rubella | Rubella Ab | Booking | If non-immune → infection control measures in pregnancy → vaccinate post-delivery [12] |
| GBS | LVS + rectal swab | 35–37 weeks | Intrapartum Abx prophylaxis (IAP) — IV penicillin/ampicillin [10] |
GBS detail: [10]
- Reservoir: GI tract (primary, 20–40% adults), vaginal colonisation (10–30% pregnant women)
- Neonatal infection: ~1/1000 births in HK
- Risk of early-onset infection 1–2% in colonised mothers
- Swab procedure: 2 separate locations without speculum — low vaginal swab at introitus + rectal swab through anal sphincter
- Screening: OGTT at 24–28 weeks [1]
- 75g OGTT — WHO/IADPSG criteria:
- Fasting ≥ 5.1 mmol/L
- 1-hour ≥ 10.0 mmol/L
- 2-hour ≥ 8.5 mmol/L
- Any ONE value abnormal = GDM
- Risk factors for GDM: obesity, age > 35, FHx DM, previous GDM, previous macrosomia, PCOS, ethnicity (Chinese)
- Management: dietary counselling → SMBG → if targets not met → insulin (metformin used increasingly)
- Monitoring: serial growth US (macrosomia, polyhydramnios); fetal surveillance from 36w; plan delivery by 40w
- BP at every visit; urinalysis for protein at every visit [3]
- First-trimester risk assessment: maternal factors + uterine artery Doppler + PlGF + MAP + PAPP-A
- High-risk women → low-dose aspirin 150 mg nocte from 12 weeks to 36 weeks
Antenatal Education and Counselling [1][14]
Patient and family education: [1]
- Antenatal classes and exercises
- Contraceptive advice
- Family as a unit
- Social support network
- Special needs for abnormal pregnancies/babies
- E.g. patient support groups
| Gestation | Counselling |
|---|---|
| Pre-pregnancy & 1st trimester | Folate, avoid teratogens, diet, exercise, stop smoking/alcohol, screening options, dating |
| Booking (10–14w) | Screening tests explanation and consent, danger signs, MCHC/hospital arrangement |
| 16–20w | Anomaly scan explanation, fetal movements (expect from 18–20w) |
| 24–28w | GDM dietary advice, kick chart counselling, signs of preterm labour |
| 28–34w | Birth planning, breastfeeding, cord blood banking, pain relief options |
| 35–37w | GBS screening, signs of labour, when to come to hospital, perineal massage |
| 37w+ | Post-dates management plan, membrane sweep, IOL discussion |
- Diet: 2000–2500 kcal/day in last 2 trimesters
- Balanced CHO, protein (60–80 g/day), fats
- Vitamins: folate (0.4 mg/day), iodine, vitamin D (note RFs)
- Exercise: reasonable activity, no need to limit beyond excessive exertion and fatigue [14]
- Coitus: no C/I unless: [14]
- Risk of miscarriage (threatened miscarriage, recurrent miscarriage Hx)
- Evidence of PROM, placenta praevia, Hx of APH
- Breast care: good personal hygiene, adequate mechanical support, counselling
- Colostrum: may leak from nipple especially in 3rd trimester and in multiparous women [14]
- Use of drugs: [14]
- Analgesics: paracetamol safe; NSAID C/I after 35 weeks (risk of premature ductus arteriosus closure)
- Vomiting: metoclopramide safe
| Red Flag | Possible Diagnosis |
|---|---|
| Severe headache + visual disturbance + epigastric pain + hypertension | Pre-eclampsia / HELLP syndrome |
| PV bleeding (any gestation) | Miscarriage, ectopic, molar pregnancy (1st tri); placenta praevia, abruption (2nd/3rd tri) |
| Absent / significantly reduced fetal movements | Fetal compromise / IUD |
| Sudden severe abdominal pain with board-like rigidity | Placental abruption, uterine rupture |
| Leaking fluid PV | PROM / PPROM |
| Fever + rigors + uterine tenderness | Chorioamnionitis |
| Painful swollen calf ± SOB | DVT / PE |
| Severe vomiting with weight loss / ketonuria | Hyperemesis gravidarum |
| Painful contractions before 37 weeks | Preterm labour |
Special Situations and Modifications
Cardiac disease in pregnancy: [15]
- Combined obstetric/cardiac clinic
- Echocardiogram at booking + 28 weeks
- Monitor for HF symptoms: SOBOE, orthopnoea, PND
- Warfarin must be stopped in 1st trimester + 2 weeks before EDC [4]
- LMWH: insufficient for mechanical prosthetic valves but safe as does not cross placenta [4]
- Epidural preferred intrapartum (↓stress on heart)
- Syntocinon instead of syntometrine (syntometrine causes intense vasoconstriction → ↑↑afterload) [15]
Thrombophilia in pregnancy: [4]
- Low-dose aspirin 100 mg nocte + LMWH for antiphospholipid syndrome
- Minimise immobility: do NOT injudiciously prescribe bed rest
- Adequate hydration, ± compression stockings
HIV-positive mother: [10]
- Avoid fetal scalp blood sampling, scalp electrode insertion, rupture of membranes
- C-section offered unless prolonged ROM / advanced labour / adequate cART (VL < 50)
- Avoid breastfeeding (unless no alternative; if on cART risk is much lower)
- Post-exposure prophylaxis for baby: zidovudine 300 mg PO BD × 7 days + lamivudine 150 mg PO BD × 7 days [10]
- ↑ risk of chromosomal abnormalities → emphasis on first-trimester combined screening / NIPT
- ↑ risk of GDM, pre-eclampsia, C-section
- May require more frequent monitoring
- Determine chorionicity at first scan (critical for management)
- More frequent growth scans (Q2w for MCDA; Q4w for DCDA)
- Screen for twin-twin transfusion syndrome (MCDA)
- Higher risk of preterm labour, pre-eclampsia, GDM
Exam Approach
- "Outline the schedule and content of routine antenatal care" — use the timeline table
- "A 32-year-old woman presents at 10 weeks. What investigations would you arrange?" — list all booking investigations with rationale
- "Discuss screening for Down syndrome in pregnancy" — cover combined first-trimester screen, NIPT, diagnostic tests
- "A woman is Rh-negative. How would you manage her pregnancy?" — anti-D timing, antibody screening, sensitising events
- OSCE station: Booking visit history taking — demonstrate systematic approach
Common Exam Traps
- Forgetting to mention dating as a key purpose of the booking scan — examiners love this.
- Confusing screening with diagnosis — a high-risk combined screen does NOT diagnose Down syndrome.
- Missing GBS screening at 35–37 weeks — commonly omitted in answers.
- Not knowing the GDM OGTT cut-offs — memorise the WHO/IADPSG criteria.
- Stating that cervical smear is "routine" in pregnancy — it is opportunistic, not routine [13].
- Forgetting that anti-D is given at 28 weeks as routine prophylaxis (not just after sensitising events).
- Not mentioning that warfarin is teratogenic in 1st trimester when discussing cardiac disease in pregnancy.
"Antenatal care is a longitudinal screening and prevention programme with the goal of a healthy mother and healthy baby. I would structure my approach chronologically: pre-pregnancy counselling, booking visit at 10–14 weeks, first-trimester screening, anomaly scan at 18–22 weeks, GDM screening at 24–28 weeks, GBS screening at 35–37 weeks, and weekly visits from 36 weeks. At every visit, I check BP, urinalysis, SFH, fetal heart, and maternal wellbeing."
High Yield Summary
Objectives of ANC: Prevention, early detection (screening), education → "Healthy mother and healthy baby."
Booking visit (10–14w): Full Hx, PE (BP, BMI, urinalysis), investigations (Hb, MCV, ABO/Rh, HBsAg, HIV, rubella, VDRL), dating US, NT scan, combined first-trimester screening.
Every visit: BP, urinalysis (protein + glucose), SFH (from 24w), fetal heart, maternal wellbeing.
Key screening milestones: 11–13+6w combined screen → 18–22w anomaly scan → 24–28w OGTT + Hb + anti-D → 35–37w GBS swab.
Risk stratification: Modified McGill score in QMH; score ≥ 2 = hospital care; 0–1 = shared care.
Vertical infections: HBV (HBIG + vaccine + maternal TDF if high VL), HIV (cART + C-section if VL > 50 + no breastfeeding), syphilis (IM penicillin), rubella (vaccinate postnatally).
Pre-eclampsia: BP + proteinuria every visit; aspirin prophylaxis for high-risk from 12 weeks.
Thalassaemia: MCV < 80 → check partner → genetic counselling → prenatal diagnosis.
Red flags: Severe headache/visual disturbance/epigastric pain (pre-eclampsia), PV bleeding, absent fetal movements, PPROM, preterm contractions.
Active Recall - Antenatal Care
[1] Lecture slides: CFB (OGPAE01-1) Perinatal Medicine, Antenatal Care and Pre-pregnant Counselling (Part I).pdf (p2, p4, p10, p37, p38, p40) [2] Senior notes: Maksim Medicine Notes.pdf (p143–144) — HBV management and maternal TDF indications [3] Senior notes: Ryan Ho Fundamentals.pdf (p191) — Obstetric Examination [4] Senior notes: Adrian Lui Obstetric Notes.pdf (p123) — Thrombophilia and Thromboembolic Diseases [5] Senior notes: Adrian Lui Obstetric Notes.pdf (p17) — Pre-pregnancy Care and Counselling [6] Lecture slides: Block C - Can we get married? Pre-marital, pre-pregnancy and prenatal counselling.pdf (p13) [7] Lecture slides: Block C - Can we get married? Pre-marital, pre-pregnancy and prenatal counselling.pdf (p13) — Lifestyle and nutrition [8] Senior notes: Ryan Ho Neurology.pdf (p175) — Spinal Dysraphism and sodium valproate [9] Senior notes: Maksim Medicine Notes.pdf (p93) — Thyrotoxicosis management in pregnancy [10] Senior notes: Adrian Lui Obstetric Notes.pdf (p35) — GBS and HIV intrapartum care [11] Senior notes: Adrian Lui Obstetric Notes.pdf (p20–21) — Booking visit, dating, history [12] Senior notes: Adrian Lui Obstetric Notes.pdf (p22) — Booking examination and investigations [13] Lecture slides: CFB (OGPAE01-1) Perinatal Medicine, Antenatal Care and Pre-pregnant Counselling (Part I).pdf (p37) — Cervical screening [14] Senior notes: Adrian Lui Obstetric Notes.pdf (p24) — Antenatal education and shared care [15] Senior notes: Adrian Lui Obstetric Notes.pdf (p119) — Cardiac disease in pregnancy
Obstetric History
A systematic record of a woman's past pregnancies, deliveries, and their outcomes, typically summarized using the gravida-para (GTPAL) system to guide current obstetric care.
Gestational Diabetes Mellitus
Glucose intolerance of variable severity with onset or first recognition during pregnancy, resulting from placental hormones that induce maternal insulin resistance.