Gestational trophoblastic disease (GTD) is a group of rare tumors that occur in pregnancy. GTD involves abnormal growth of cells inside a woman's uterus and usually starts in the tissue that would normally become the placenta, in the layer of cells called the trophoblast that normally surrounds an embryo.

Gestational trophoblastic disease is a mostly benign condition, that does not metastasize or invade deeply into tissue though it occasionally can be cancerous (malignant). With GTD it’s possible for a fetus to also develop during these pregnancies. 

There are two types of GTD: Hydatidiform mole (HM) and gestational trophoblastic neoplasia (GTN).

Types of Gestational Trophoblastic Disease

Hydatiform mole (also called a molar pregnancy or H.mole) comprises 80% of all GTD.

• Complete mole (without a fetus)
• Incomplete/partial mole (without a fetus)

Gestational trophoblastic neoplasia (GTN):

• Invasive Mole Choriocarcinoma (a type of cancer)
• Placental-site trophoblastic tumor (PSTT)
• Epithelioid trophoblastic tumor (ETT)