Antenatal fetal surveillance — structured oral station (12 minutes)

Opening prompt — "How will you monitor her baby?"

Model response — lead with the modality and the reason: ^[1]

• "For a woman with type 1 diabetes and a normally grown fetus, I would use the modified biophysical profile — the non-stress test plus amniotic fluid volume — weekly or twice weekly from 32 to 34 weeks, depending on her control and comorbidity."^[1]
• "The reason is that diabetes puts the fetus at risk of acute compromise — and the CTG and BPP are acute markers of current acid-base status. Doppler is reserved for fetal growth restriction, where it reads placental function, and her fetus is growing normally."^[1]

Probe 1 — "Describe the modified BPP and how it compares to the full BPP."

• "The modified BPP is the non-stress test plus amniotic fluid volume. It performs comparably to the full five-component biophysical profile while being quicker and less operator-dependent, which is why it is the workhorse of high-risk surveillance."^[1]
• "The full BPP adds fetal movement, fetal tone and fetal breathing, scored 0 or 2 each, out of 10. Eight to 10 is normal, 6 equivocal, under 6 abnormal."^[3]
• "The biophysical variables are depressed progressively by hypoxia, so a normal BPP correlates with a normal fetal pH."^[3]

Probe 2 — "Why not Doppler in this woman?"

• "Doppler reads placental resistance — the chronic process of failed placentation. In a normally grown fetus with normal Dopplers, it does not add benefit, and the Alfirevic Cochrane review found it reduces perinatal death specifically in high-risk pregnancy where placental insufficiency is the concern — most clearly FGR."^[2]
• "If her fetus became growth-restricted, I would switch the primary modality to umbilical artery Doppler. The modality is chosen by the pathology, not by habit."^[1][2]

Probe 3 — "What does a reactive non-stress test look like at 34 weeks?"

• "At 32 weeks and over, a reactive trace needs two or more accelerations of at least 15 beats per minute for at least 15 seconds in a 20-minute window. Before 32 weeks the threshold is lower — 10 beats for 10 seconds — because preterm accelerations are smaller."^[1]
• "A reactive trace is reassuring for the short term, but it does not predict the days ahead — which is why we repeat it. A non-reactive trace prompts extension, vibroacoustic stimulation, and assessment for reversible causes like a sleeping fetus or maternal medications."^[1]

Probe 4 — "She reports reduced fetal movements. What do you do?"

• "I assess her the same day. Reduced movements are never dismissed. I take a focused history, perform a cardiotocograph, and — given her diabetes and the history — arrange a growth scan with amniotic fluid volume and, if there is any growth concern, a Doppler."^[1]
• "If the CTG and scan are normal, I reassure her and give a clear safety-net for when to return. If anything is abnormal, I escalate to delivery planning. The principle is always to act — reduced movements may be the first sign of fetal compromise."^[1]

Probe 5 — "Is routine surveillance justified in low-risk pregnancy?"

• "No. No surveillance test has been shown to reduce stillbirth in a low-risk population in a randomised trial, and ACOG Practice Bulletin 229 does not recommend routine surveillance of low-risk pregnancy. Surveillance is for pregnancies at increased risk of fetal death — and this woman, with diabetes, qualifies."^[1]

Probe 6 — communication: "Explain the plan to her in plain language."

Three of the eight domains are scored here. Say the words out loud. ^[1]

• "Because you have diabetes, we watch your baby a little more closely from now until the birth — usually once or twice a week. It is a short trace of the baby's heartbeat and a quick scan to check the fluid around the baby." ^[1]
• "If everything looks well, that is reassuring for the next few days, and we repeat it. If the baby is quieter than usual, or the trace shows anything we want to check, we bring you in the same day and look more closely."
• "The most important thing is that you know your baby's pattern, and if it changes — especially if movements are reduced — you call us straight away. We would always rather check and find all is well than have you wait."
• Check understanding by asking her to say the plan back, and document the discussion.