What is a four-dimensional (4D) ultrasound?
A standard ultrasound gives two-dimensional cross-section images. 3D ultrasound builds a surface image from these sections; 4D ultrasound shows that image moving, in real time. In this way the baby’s facial features and movements can be seen.
The 4D image can be a meaningful experience for families; however, the main part of the medical assessment is done with the two-dimensional detailed scan.
What is a detailed ultrasound for?
In a detailed ultrasound, the baby’s organs, development, the placenta and the amniotic fluid are examined systematically. It is usually done in the second trimester, between certain weeks. Ultrasound can show many structural differences, but it cannot detect every condition; this limit is explained to you clearly at the appointment.
Doppler ultrasound
Doppler ultrasound assesses blood flow in the vessels between mother and baby. It is used when the baby’s growth is suspected to have slowed, in situations such as high blood pressure in the mother, or in other cases where the doctor considers it necessary.
What affects the image?
The baby’s position, the amount of amniotic fluid, the position of the placenta and the thickness of the mother’s abdominal wall all affect image quality. If the baby has turned their face away or is covering it with their hands, a clear 4D image may not be possible that day; in that case the scan can be planned for another time.
Ultrasound in gynaecology
Ultrasound is used not only in pregnancy but also to assess the womb and ovaries. Findings such as fibroids, cysts and the thickness of the womb lining are examined with a vaginal or abdominal (through the tummy) ultrasound. Which method is suitable is decided at the appointment.
The information on this page is for general guidance only; an examination is needed for diagnosis and treatment. Every person’s situation is different.
