Growth Scan

A growth scan uses ultrasound to assess your baby's growth, position, fluid and placental features during pregnancy.

A growth scan, also called a third-trimester scan or fetal growth ultrasound, uses sound waves to assess how your baby is growing. The sonographer measures parts of the baby, checks movement and heartbeat, looks at the placenta and estimates the amount of amniotic fluid. The scan also considers position and blood flow when Doppler assessment is needed.

The result is interpreted with your pregnancy history and earlier measurements. One scan is a snapshot; a pattern across appointments can be more useful for deciding whether monitoring or another plan is needed.

Before the scan, you may be asked about dates, symptoms and your pregnancy history. During the appointment, you lie comfortably while gel is placed on your abdomen and the probe is moved over the skin. The sonographer records measurements and may assess fluid, placenta and blood flow. Afterward, your maternity team explains the findings and next step.

Ultrasound does not use ionising radiation. A trained professional uses the equipment for a medical purpose and keeps the examination focused on the checks needed for your care. You may feel pressure from the probe, but the scan should not cause significant pain. Tell the sonographer if positioning is uncomfortable.

Your choices depend on the findings, gestational age, symptoms and local maternity plan. You may be offered routine follow-up, a repeat scan, Doppler monitoring, an obstetric review or a discussion about timing and place of birth. Ask what the measurement means for your individual pregnancy and which result would change the plan.

A growth scan can assess size without proving why a baby is measuring differently. Measurements are estimates and can be affected by position and technical visibility. Fluid and placental findings add context. If you have reduced movements, contact your maternity service promptly rather than waiting for a scheduled scan.

Your maternity team may recommend a scan when growth needs closer monitoring, or when a pregnancy feature could affect fluid, placenta or timing of birth. Reasons may include [Fetal Growth Restriction](/conditions/fetal-growth-restriction/), [Gestational Diabetes](/conditions/gestational-diabetes/), [Twin and Multiple Pregnancy](/conditions/multiple-pregnancy/), or concerns about fluid such as [Oligohydramnios](/conditions/oligohydramnios/) and [Polyhydramnios](/conditions/polyhydramnios/).

You check in and discuss the reason for the scan. You expose the abdomen as needed, lie in the advised position and have gel applied. The sonographer takes images and measurements, sometimes adding Doppler checks. A clinician may review the report and explain whether you need another appointment or additional monitoring.

There is usually no recovery period, and you can continue normal activities unless your maternity team advises otherwise. Results may be discussed on the day or sent for review. If a finding needs confirmation, a repeat scan or specialist appointment may be arranged. Follow your maternity service's advice about movements and symptoms between visits.

Ultrasound cannot answer every question about a baby's health, and estimated size is not an exact weight. Images may be limited by fetal position or the view through the abdomen. A reassuring scan does not replace attention to symptoms. Contact your maternity service urgently for reduced fetal movements, vaginal bleeding, leaking fluid or severe abdominal pain.

Depending on your situation, monitoring may also include abdominal examination, blood-pressure checks, movement assessment, fetal heart-rate monitoring or Doppler follow-up. A [3D/4D Ultrasound](/technology/3d-4d-ultrasound/) provides a different type of image and is not automatically a substitute for the measurements used in a growth assessment.

Arrange the scan through your maternity team or a qualified ultrasound service that can connect findings with obstetric care. Bring your pregnancy notes and ask who will explain the report. Confirm when you will receive results, which symptoms need urgent contact and whether another scan is planned.