Screening for molar pregnancy

A molar pregnancy occurs when the fertilisation of the egg by the sperm goes wrong and leads to the growth of abnormal cells or clusters of water filled sacs inside the womb. This condition is part of a group of tumours known as gestational trophoblastic tumours (GTT). 

Screening means testing for early stages of a disease before there are any symptoms. Before doctors can screen for any type of disease or condition, they must have an accurate test to use. The test must be reliable in picking up diseases or conditions that are there. And it must not give false positive results in people who do not have the disease or condition.

The best way to pick up a molar pregnancy early is to have the routine antenatal care provided by your doctor and midwife during pregnancy. They will closely monitor you and do various tests to make sure your baby is developing normally.

Early in your pregnancy you will have an ultrasound scan to look for any abnormalities. The use of ultrasound scans means that most molar pregnancies are now picked up at a very early stage. Ultrasound scans are a good way of diagnosing a complete molar pregnancy, but is not so good at picking up partial molar pregnancies (although this is still likely to be picked up by other routine tests). Your doctor will also do tests for molar pregnancy or GTT if you have any abnormal symptoms.

If you have a miscarriage or abortion, doctors also check the foetal tissue and placenta for any abnormalities and this is the most common way that a partial molar pregnancy is diagnosed.