Hydatidiform mole

Alternative names:

hydatid mole

Definition:

A rare mass or growth that may form inside the uterus at the beginning of a pregnancy. See also choriocarcinoma.

Causes, incidence, and risk factors:

Hydatidiform moles arise from fetal tissue and, therefore can only occur in conjunction with the early stages of pregnancy. The mass is usually placental material that grows uncontrolled. Frequently there is no fetus at all. The cause of this developmental disorder is not completely understood. Potential causes may include defects of the ovum (egg), abnormalities within the uterus, and/or nutritional deficiencies. The incidence in the U.S. is 1 out of 1500 pregnancies; however, it occurs in up to 1 out of 125 pregnancies in Mexico and some Asian countries. Women under 20 or over 40 years old have an increased incidence. Risk factors include low socioeconomic status and diets low in protein, folic acid, and carotene.