Growth Scan

A growth scan checks how well your baby is growing and is usually performed in the third trimester of pregnancy. It assesses fetal growth and vital signs, and the term is used by many hospitals and ultrasound centres.

In most places a growth scan does not aim to exclude fetal anomalies. At London Pregnancy Clinic we go further, checking your baby's growth as part of a fuller assessment. You can see our full range on our scans page.

A growth scan is usually performed in the third trimester of pregnancy, when it is most useful for monitoring how your baby is growing. It checks fetal growth and vital signs at this later stage.

That said, at London Pregnancy Clinic we check fetal growth at any scan and at any stage of pregnancy, so growth can be assessed earlier where there is a reason to.

A growth scan checks how well your baby is growing, while a developmental scan aims to exclude fetal problems that have a late manifestation. In most places a growth scan does not set out to look for anomalies.

At our Developmental and Wellbeing Scan we check fetal structures — especially the brain, heart and kidneys — as well as growth, wellbeing, and the condition of the placenta and amniotic fluid volume. This scan includes the growth scan.

Yes. According to a 2020 study across two UK centres — King's College Hospital, London and Medway Maritime Hospital, Gillingham, Kent — around a quarter (24.8%) of all fetal anomalies were first detected in the third trimester at 35–37 weeks (Ficara et al., 2020).

This is why our Developmental and Wellbeing Scan looks at fetal structures such as the brain, heart and kidneys to exclude anomalies that develop late or were previously undiagnosed, alongside checking your baby's growth.

Not quite. In the third trimester, London Pregnancy Clinic performs a Wellbeing and Developmental Scan, which includes the growth scan as one part of a more comprehensive assessment.

As well as checking your baby's growth, this scan assesses fetal wellbeing, fetal structures, and the condition of the placenta and amniotic fluid volume — giving a fuller picture than a growth check alone.

No referral is needed to book a growth scan with us. You can arrange your appointment directly through our online booking, or by calling the clinic on 020 3687 2939.

If you would like to discuss which scan is most appropriate for your stage of pregnancy before booking, our team is happy to help. You can book your scan when you are ready.

Your scan is carried out by our specialists, who are experts in fetal anomaly detection at any stage of pregnancy. This expertise means growth is assessed as part of a thorough clinical picture.

Because our third-trimester scan combines growth with a developmental and wellbeing assessment, the same appointment covers fetal structures, growth, wellbeing, the placenta and amniotic fluid volume.

A growth scan gives an estimated fetal weight based on measurements of your baby's head, abdomen and thigh bone. Because it is an estimate, the figure can differ from your baby's actual birth weight, and factors such as your baby's position can affect the measurements.

For this reason, clinicians look at the pattern of growth across scans rather than relying on a single number. If there is any question about your baby's size, a repeat scan a few weeks later usually gives a much clearer picture.

A baby measuring smaller than expected is described as small-for-dates or small-for-gestational-age, usually meaning an estimated weight in the smallest 10 per cent for their stage. Many of these babies are simply constitutionally small and perfectly healthy (RCOG).

In a smaller number of cases it can suggest fetal growth restriction, where the placenta may not be working as well as it should. This is why a small measurement often leads to closer monitoring — such as a Doppler scan or a repeat growth scan — rather than immediate concern.

No. A full bladder can be helpful for some early-pregnancy scans, but it is not needed for a third-trimester growth scan. You are welcome to attend having emptied your bladder, which is usually more comfortable.

There is no other special preparation. Loose, two-piece clothing that lets us reach your bump easily can make the appointment more relaxed.

There is no fixed limit. Where growth is being monitored, scans are usually spaced around three to four weeks apart, because a baby needs time to grow measurably between assessments. Your midwife or obstetrician will advise on timing based on your individual pregnancy.

Ultrasound has been used in pregnancy for decades and has no known risk to you or your baby when performed for a genuine clinical reason (NHS), so appropriate repeat scans are considered safe.

A growth scan can also flag a baby that is measuring larger than expected, sometimes called large-for-dates. This is based on an estimated weight, so it is an indication rather than an exact figure.

If your baby is measuring large, your maternity team may discuss what this means for your birth plan. As with a small measurement, the trend across scans is more informative than any single result.

Yes. A growth scan is a standard ultrasound examination, which is painless and has no known risks to you or your baby (NHS). It uses sound waves rather than radiation to create the images.

A scan only ever shows one moment in time, though, so keep attending your routine antenatal appointments. If your baby's movements slow down or change, contact your maternity unit straight away — do not wait for a scan appointment.

Amniotic fluid is measured at every growth scan. A result outside the expected range is common and often means more monitoring rather than a problem.

We explain both in full: polyhydramnios when there is more fluid than expected, and oligohydramnios when there is less. If you have had a sudden gush of fluid or your baby is moving less, contact your maternity unit the same day rather than waiting for a scan.