Ultrasound Fetal Growth Scan

The best time for a fetal growth scan is in the third trimester—typically between 28 and 36 weeks, most commonly around 32–36 weeks—when size, amniotic fluid and fetal position can be assessed reliably. If there are risk factors (hypertension, diabetes, decreased movements) scans may start earlier and be repeated every 1–4 weeks to monitor growth and wellbeing.

No — a 32‑week growth scan isn’t routine for every pregnancy. Most services offer dating and anatomy scans; a third‑trimester growth scan is arranged if there are concerns or risk factors (for example high blood pressure, diabetes, reduced fetal movements, suspected small/large baby, placental issues, or multiple pregnancy). Your midwife or obstetrician will recommend it if clinically indicated.

Fetal growth scans usually take about 20–45 minutes. A routine growth scan is often 20–30 minutes, while more detailed or technically challenging exams (multiple babies, low fetal movement, maternal body habitus, or extra measurements) can take up to 45 minutes. Allow extra time for arrival, preparation and any discussion with the sonographer or doctor afterward.

No — a 28-week growth scan is not routine for everyone. Standard care usually includes early and anomaly scans; a growth scan around 28 weeks is offered only if there are concerns or risk factors (small or large fundal height, reduced fetal movements, high BMI, gestational diabetes, hypertension, multiple pregnancy, prior growth problems, placenta issues). Local practice varies, so ask your provider.

Growth scans cannot detect all fetal problems. They effectively monitor size, growth trends, placental position and major structural issues, but subtle anomalies, genetic or metabolic disorders, and some cardiac or neurological problems may be missed. Accuracy depends on gestational age, equipment and operator skill. If concerns arise, further tests (detailed anomaly scans, Doppler studies, fetal echo or genetic testing) are recommended.

At seven months’ gestation (about 28–31 weeks), a typical fetus weighs roughly 1,000–1,500 grams (2.2–3.3 pounds). Exact weight depends on the specific week and individual factors; about 1,000 g at 28 weeks rising to approximately 1,300–1,500 g by 30–31 weeks. Healthcare providers monitor growth with ultrasound and percentiles to ensure healthy development.