Ultrasound is a scanning technique used during pregnancy to examine the progress of the growing foetus, as well as the condition of the uterus, placenta and amniotic fluid.
It works through the use of high frequency soundwaves, which are sent through the uterus. These soundwaves bounce off the baby and echo. The echo transmits as an image, which details the location, movement and position of the baby.
The biggest echoes are created by the hardest tissues, such as bones. These echoes generate a white image, while the smaller echoes from softer tissues produce grey images. Fluid, such as amniotic fluid, will show as black as the echo will travel through, rather than bounce off.
An ultrasound is normally performed by a specialist medical practitioner called a sonographer. The songographer will study the images provided by the ultrasound and assess the condition of the pregnancy.
Specialist doctors, known as fetal medicine specialists, can also carry out ultrasound but only if a significant problem arises during the pregnancy.
In a normal pregnancy, ultrasound scans are performed at around week 12 of pregnancy, and again at week 20. These scans are often an exciting event for parents as ultrasound produces an excellent view of the baby. It captures an incredible depth of detail, which includes the ability to determine the sex of the child, which is possible at the 20-week scan.