Gestational Trophoblastic Disease

While most GTD tumors are benign (noncancerous), some may become malignant (cancerous). The only way to prevent GTD is not to become pregnant.

Types of gestational trophoblastic disease

Gestational trophoblastic disease has two categories:

•  Hydatidiform moles (HM)
•  Gestational trophoblastic neoplasia (GTN)

Hydatidiform moles

A hydatidiform mole is also known as a molar pregnancy, and it is the most common type of gestational trophoblastic disease. In a molar pregnancy, tumors that can look like sacs of fluid form in the uterus. There are two types of hydatidiform moles:

• Partial molar pregnancy: The fertilized egg has normal DNA from the mother but has two sets of DNA from the father. A fetus does not fully develop or does not develop at all, and the cells that were meant to form the placenta are abnormal.
• Complete molar pregnancy: The fertilized egg does not have DNA from the mother and has two sets of DNA from the father. The cells that were meant to form the placenta are abnormal, and a fetus does not form.

Gestational trophoblastic neoplasia

There are several types of malignant gestational trophoblastic neoplasia (GTN):

• Choriocarcinoma: This cancerous tumor forms from trophoblast cells and can spread into the muscles of the uterus, nearby blood vessels, and other organs. It can grow and spread more quickly than other GTNs. Sometimes choriocarcinomas develop from tissue left in the uterus after a miscarriage or delivering a healthy baby.
• Invasive mole: Although an invasive mole is a type of molar pregnancy, it is considered a GTN because of its potential to grow and spread. It may grow into the muscle layer of the uterus.
• Placental-site trophoblastic tumor and Epithelioid trophoblastic tumor: These rare tumors develop where the placenta attaches to the uterus. Symptoms may not appear until years after a full-term pregnancy, a miscarriage or treatment for a molar pregnancy.

Gestational trophoblastic disease risk factors

Some factors can increase a woman’s risk of developing gestational trophoblastic disease. They include:

• Being pregnant when you are younger than 20 or older than 35
• Having had a previous molar pregnancy
• Previous miscarriage
• Women from Southeast Asia and those with low dietary carotene also have a higher risk of molar pregnancy and GTN

The great majority of women with risk factors will not get gestational trophoblastic disease. However, if a woman does have risk factors it’s a good idea to discuss them with a health care provider. This may lead to more frequent monitoring during early pregnancy.