Growth scan: what to expect

The sonographer measures parts of the baby such as the head, abdomen and thigh bone. These measurements are combined to estimate growth and are considered alongside your dates and earlier scans. The scan can also review movement, heartbeat, the baby's position, amniotic fluid and the placenta. A result outside the expected pattern does not by itself explain why it happened; your clinician may compare it with previous measurements or arrange another assessment.

You may hear this called a third trimester scan or fetal growth ultrasound. It is different from a detailed anatomy scan because its focus is growth and current wellbeing.

Follow the preparation instructions given by your maternity unit. Wear clothing that allows easy access to your abdomen and bring your pregnancy notes if requested. You usually lie back while gel is placed on the skin and a probe is moved over your abdomen. The appointment may take longer when the baby's position makes images difficult. Ask whether you can have someone with you and when the report will be explained.

A growth scan is an assessment, not a prediction of exactly how your baby will grow or when labour will begin. Your team may suggest monitoring, another scan or a change in care based on the whole picture.

Contact your maternity team promptly if you notice reduced or changed fetal movements, vaginal bleeding, leaking fluid, regular painful contractions, severe abdominal pain, a severe headache or changes in vision. These concerns need clinical advice even if a recent scan was reassuring. Use the urgent maternity route recommended for your pregnancy rather than waiting for the scan report.

Ask what measurements were taken, whether growth is following the previous pattern, and what the fluid and placenta findings mean. You can also ask whether another scan or monitoring is planned, who will contact you with the result, and which symptoms should prompt an urgent call.