Invasive mole and choriocarcinoma
Anything that can increase your risk of getting a disease is called a risk factor. Different conditions have different risk factors. Having one of these risk factors doesn't mean you will definitely get invasive mole or choriocarcinoma.
Having a previous molar pregnancy is the main known risk factor for:
invasive mole and
choriocarcinoma
Invasive mole and choriocarcinoma are very rare. The number of women who develop one of these conditions following a molar pregnancy is small.
A molar pregnancy occurs when the fertilisation of the egg by the sperm goes wrong. This leads to the growth of abnormal cells or clusters of water filled sacs inside the . Usually any molar cells left after treatment will die off by themselves. But sometimes they will keep growing and become cancerous. This is called an invasive mole or persistent trophoblastic disease (PTD).
About 13 to 16 out of every 100 women (about 13 to 16%) who have had a complete molar pregnancy will go on to develop an invasive mole. For women who have had a partial molar pregnancy, the risk is only 1 in 100 women (1%).
Read more about molar pregnancy
Choriocarcinomas are extremely rare cancers. They are more likely to develop after a molar pregnancy. But they can also happen following a full term pregnancy, miscarriage, ectopic pregnancy or abortion.
Researchers aren’t completely sure what causes molar pregnancies. But we do know of some factors that increase a woman's risk of developing one.
Last reviewed: 04 Sept 2025
Next review due: 04 Sept 2028
An invasive mole and choriocarcinoma are rare cancers. They grow from the tissue that forms in the womb during pregnancy.
Some women may not have any symptoms. This is particularly the case for a woman with an invasive mole as these are usually picked up during follow up for a molar pregnancy.If there are symptoms, the main symptoms for an invasive mole or choriocarcinoma is vaginal bleeding.
If you develop an invasive mole or choriocarcinoma it usually shows up on some tests before you notice any symptoms. Your specialist team will then ask you to go in to see them.
The stage of an invasive mole or choriocarcinoma tells you how far it has spread. Your doctors will look at this and other risk factors to plan your treatment.
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