What to know about a 28-week growth scan

The sonographer measures parts of the baby's head, abdomen and thigh bone. These measurements are considered together and compared with earlier information to estimate growth. The scan may also record the baby's position, movements, the amount of amniotic fluid and where the placenta lies.

An ultrasound estimate is not an exact measurement of weight. A single result is interpreted alongside your pregnancy dates, previous scans and clinical history. If a measurement is smaller or larger than expected, your maternity team may recommend another scan or additional checks to understand the growth pattern.

Follow the imaging centre's instructions about drinking water, because bladder preparation can vary. Wear clothing that makes your abdomen easy to reach and bring previous scan reports if they are not already in your record. During the appointment, gel is placed on the abdomen and a handheld probe creates the images.

Afterwards, ask whether growth appears consistent with the expected pattern, whether the placenta and fluid were clearly assessed, and whether follow-up is planned. Continue routine antenatal appointments even when the scan is reassuring.

Contact your maternity unit promptly if your baby's usual movement pattern reduces or changes; do not wait for a booked scan. Seek urgent assessment for vaginal bleeding, leaking fluid, severe or persistent abdominal pain, regular painful tightenings, a severe headache with visual changes, sudden marked swelling, breathlessness or feeling acutely unwell.

You may want to ask: Are the measurements following the expected growth pattern? Was the baby's position suitable for all planned views? How did the amniotic fluid and placenta appear? Do I need repeat imaging, and what specific change would prompt an earlier review?