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OG8.{4,8} | Maternal and Fetal Surveillance — SDL Guide (Part 3)

Applied Clinical Decision-Making: Integrating Surveillance Findings

Integrating surveillance findings requires the clinician to weigh multiple parameters simultaneously, understand their relative sensitivity and specificity, and translate them into a coherent management plan that accounts for gestational age, the underlying diagnosis, available facility capacity, and the woman's values. This is the 'applied or supervised practice' step — the ability to not just recall surveillance criteria but to apply them in a dynamic clinical situation.

Case scenario walkthrough:
A 32-year-old G2P1L1 woman with gestational hypertension presents at 34 weeks with reduced fetal movements over 48 hours. Her BP is 150/95 mmHg (previously 130/85 at her last visit). SFH is 29 cm (consistent with 34 weeks — no discordance). She performs her DFMC count: 7 movements in 12 hours (below the 10-movement threshold).

Step 1 — Evaluate the clinical severity:
Reduced DFMC + rising BP trend = two simultaneous concerns. The DFMC is reduced (7 < 10 threshold), which is the immediate trigger for urgent fetal evaluation. The BP of 150/95 mmHg qualifies as significant hypertension (single reading, confirm in 4 hours; if confirmed, treat).

Step 2 — NST:
NST is performed: non-reactive over 40 minutes (no accelerations), with late decelerations noted on 2 occasions. This is a non-reassuring NST in the context of hypertension — the late decelerations suggest uteroplacental insufficiency.

Step 3 — BPP:
Emergency BPP shows: NST component non-reactive (0), fetal breathing movements present for 35 seconds (2), gross body movements ≥3 (2), fetal tone present (2), AFI 4.5 cm (oligohydramnios, <5 cm = score 0). Total BPP = 6/10.

Step 4 — Doppler:
Umbilical artery Doppler shows absent end-diastolic flow (AEDF). At 34 weeks, AEDF with BPP 6 = deliver.

Step 5 — Decision:
At 34 weeks with BPP 6 + AEDF + oligohydramnios in the context of gestational hypertension: administer corticosteroids (betamethasone 12 mg IM × 2 doses 24 hours apart for lung maturation), initiate antihypertensive therapy, and plan delivery within 24–48 hours. If the BPP deteriorates to ≤4 in the interim, deliver immediately. This decision integrates gestational age (34 weeks = borderline viability for prematurity complications), severity of fetal compromise, maternal condition, and facility capacity.

Self-Assessment: Maternal and Fetal Surveillance

Competency OG8.4 (SH level) and OG8.8 (KH level) require you to be able to perform and interpret maternal and fetal surveillance in a clinical environment — OG8.4 demands observed performance, meaning you must demonstrate the skill to an assessor, not merely describe it. The questions below target the cognitive level of final examinations: not simple recall, but application of surveillance criteria to clinical scenarios. As you work through these questions, notice which elements require you to retrieve a specific threshold (the exact NST reactive criteria, the exact BPP scoring cutoffs, the AFI oligohydramnios threshold) and which require you to reason through a clinical decision tree (what comes after a non-reactive NST? what is the management of BPP 6 at 36 weeks vs at 30 weeks?). Threshold retrieval can be addressed by systematic memorisation; clinical decision-making requires deliberate practice in interpreting clinical vignettes, which is best acquired through supervised bedside exposure and OSCE preparation. The self-assessment questions below are structured at the same cognitive level as final examination questions — they require application and analysis, not simple recall. Work through each question before checking your answer, and if you are uncertain, identify the specific gap in your knowledge (threshold value? Interpretation framework? Clinical decision algorithm?) so that you can target your revision precisely.

Self-check questions to guide your review:
- State the exact criteria for a reactive NST. How long do you wait before calling an NST non-reactive? What is the next investigation after a non-reactive NST?
- A woman at 38 weeks with IUGR has a BPP of 6/10 (absent breathing movements, all other parameters normal). What is the BPP interpretation and management at this gestational age?
- Define oligohydramnios by both the AFI method and the single deepest pocket (SDP) method. At what gestational age does oligohydramnios become an indication for delivery?
- What is the significance of absent end-diastolic flow versus reversed end-diastolic flow on umbilical artery Doppler, and how does your management differ?
- At what gestational age is first-trimester ultrasound (CRL) most accurate for gestational dating, and why is it superior to LMP in certain clinical situations?