Find out about gestational trophoblastic disease (GTD), where it starts, and how rare it is.
What gestational trophoblastic disease is
Gestational trophoblastic disease is the name for abnormal cells or tumours that grow from the tissue that forms in the womb during pregnancy. It is called GTD for short and is very rare.
GTD can be non cancerous (benign) or cancerous (malignant).
- molar pregnancy
- persistent trophoblastic disease (PTD)
- placental site trophoblastic tumour (PSTT)
Although GTD starts in the womb, it behaves very differently from a cancer of the womb. It is also treated differently.
If you are looking for information about womb cancer (also known as uterine or endometrial cancer) go to our womb cancer section.
How GTDs develop
Gestation means pregnancy and trophoblast describes cells that are part of the normal development of a baby. Usually, after a sperm fertilises an egg, new cells grow within the womb to form an embryo. As the embryo grows, its cells start to specialise.
Some cells start to form the baby (foetus) and others form the placenta. The placenta protects and nourishes the baby during pregnancy.
The first layer of cells that develops into the placenta is called the trophoblast. The trophoblast produces tiny, finger-like, outgrowths known as villi. These villi attach the placenta to the lining of the womb.
In a molar pregnancy
There is a mistake when the sperm fertilises the egg. The foetus either doesn’t develop at all, or it partly forms but can't grow normally. The villi may swell up and grow in clusters, a bit like bunches of grapes.
Molar pregnancy is the most common type of GTD and can be either a partial or complete mole. These tumours are not cancerous – they are benign. But, rarely, a molar pregnancy can become cancerous and can spread to other parts of the body.
In a persistent GTD or choriocarcinoma
Some trophoblastic cells grow abnormally and develop into a tumour. These tumours are cancerous and can spread outside the womb.
Placental site trophoblastic tumours
They can happen after any type of pregnancy, including molar pregnancy, miscarriage or a full term normal pregnancy. These cancers can occur several months, or even years later. They develop in the area where the placenta joined the lining of the womb (uterus). They can grow into the muscle layer of the womb and sometimes can spread to other parts of the body.
Treatment that works very well is available for all types of GTD. Nearly all of them are curable, whether they are cancerous or non cancerous.
Other terms used to describe gestational trophoblastic disease (GTD)
The medical descriptions for gestational trophoblastic disease are all quite long and can sound complicated. Other terms that may be used for these types of tumours include:
gestational trophoblastic tumour (GTT)
gestational trophoblastic neoplasia (GTN)