Antenatal Monitoring: NSTs, Growth Scans, and Fetal Surveillance
Most pregnancies are monitored through routine visits alone. But for pregnancies with certain risk factors — or once you're past your due date — additional testing (broadly called antenatal surveillance) checks in on the baby more directly between visits. None of these tests are things to seek out on your own; your provider will tell you if and when any of it becomes relevant for your specific pregnancy.
Last updated August 2026
Kick counts are the baseline everyone can do
Tracking fetal movement yourself is the simplest form of monitoring, and something every pregnant person can do without any special testing — the Maternity Companion tool in this app has a kick-counting feature built in. A real, sustained drop in your baby's usual movement pattern is worth a same-day call regardless of whether any of the testing below is part of your care.
The non-stress test (NST)
An NST uses an external monitor, usually worn for 20-40 minutes, to track the baby's heart rate and how it responds to movement. It's commonly used for a pregnancy past its due date, after reporting reduced fetal movement, or for certain risk factors that warrant closer watching. A "reactive" result — the heart rate appropriately speeding up with movement — is the reassuring outcome. A "non-reactive" result means the test didn't show that expected pattern in the time given; it's a reason for more evaluation (often more monitoring time, or a follow-up test), not automatically an emergency.
The biophysical profile (BPP)
A BPP combines an NST with an ultrasound checking four additional things: fetal breathing movements, body movement, muscle tone, and the amount of amniotic fluid. Each of the five components is scored, and the total is what your provider is actually looking at — it's a composite picture of how the baby is doing right now, not a single pass/fail result on one measurement.
Growth scans and Doppler studies
A growth scan is a dedicated ultrasound specifically checking the baby's size and growth trend over time, used when there's a specific reason to watch growth closely — suspected growth restriction, twins, or certain risk factors. Umbilical artery Doppler studies use ultrasound to look at blood flow through the umbilical cord itself, and are specifically used when growth restriction is a concern, since they can show whether the placenta is delivering blood flow adequately.
When this actually gets added to your care
Common reasons antenatal testing gets added include being past your due date, reporting reduced fetal movement, gestational diabetes, hypertensive disorders like preeclampsia, carrying twins, a prior stillbirth, or advanced maternal age — but this list is context, not a self-triage tool. Your provider will tell you directly if and when any of this becomes relevant for your specific pregnancy.
Worth discussing with your provider
Educational information only — general patterns that vary by person. This is not medical advice, a diagnosis, or a substitute for care from your own clinician.
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