Why is 3D/4D ultrasound used in an anomaly scan?

A standard ultrasound creates flat images, while 3D ultrasound builds a still, volumetric view and 4D ultrasound adds movement over time. These views can help the sonographer examine selected areas from different angles, such as the face, limbs, spine or body surface. They may also help explain an observation to you. The main assessment still depends on the full scan, measurements, the baby's position and the sonographer's clinical judgement. A detailed-looking image is not itself a diagnosis, and a limited view can occur when the baby is facing away or movement makes imaging difficult.

Follow the appointment instructions about food, fluids and clothing. During the examination, remain as comfortable as possible and tell the sonographer if you need a pause. You can ask which structures are being assessed and whether an additional view is being used because a particular area was difficult to see. If the scan identifies a concern or an incomplete view, your maternity team may explain whether repeat imaging or specialist review is needed.

The use of 3D/4D imaging does not by itself indicate that something is wrong. Contact your maternity team promptly for vaginal bleeding, leaking fluid, severe abdominal pain, regular painful contractions or noticeably reduced fetal movement after you have been advised how to monitor it. These symptoms need clinical assessment regardless of what an ultrasound image shows.

Ask what part of the anomaly scan needs an additional view, whether the standard assessment was complete, when results will be discussed and what follow-up would be arranged if an area cannot be seen clearly.