Research on HG's short- and long-term effects is desperately needed and needed now. We need to do more to find a cure for this disease that has such devastating effects on a growing number of soon-to-be mothers.
Gestational Trophoblastic Disease
Gestational trophoblastic disease (GTD) or molar pregnancy does not cause HG, however, women with GTD may have symptoms that resemble HG, such as nausea and vomiting. GTD should be ruled out in these women and immediate intervention given to avoid metastasis or other complications. The information here is presented as a reference for health professionals.
Gestational Trophoblastic Disease
Adapted from Merck: www.merck.com
Neoplasms of trophoblastic origin can follow a spontaneous abortion, an ectopic pregnancy, or a full-term pregnancy. A hydatidiform mole is a pregnancy in which the villi have become hydropic and trophoblastic elements have proliferated. Chorioadenoma destruens (invasive mole) is a local invasion of the myometrium by the hydatidiform mole. Choriocarcinoma is an invasive, usually widely metastatic tumor composed of malignant trophoblastic cells without hydropic villi. Placental site trophoblastic tumor, consisting of intermediate trophoblastic cells that persist after a term pregnancy, is rare.
A hydatidiform mole is more common after pregnancies in very young (< 17 yr) or older (late 30s and 40s) patients, occurring in about 1 in 2000 gestations in the USA. For unknown reasons, the incidence in Asiatic countries approaches 1 in 200. More than 80% of hydatidiform moles are benign and spontaneously regress. However, 15 to 20% tend to persist and 2 to 3% are followed by choriocarcinoma (in about 1 in 25,000 to 45,000 pregnancies).
Symptoms, Signs, and Diagnosis
A hydatidiform mole is often manifested within 10 to 16 wk after conception by a rapidly enlarging uterus, which is often larger than expected for estimated gestational age. Vaginal bleeding, lack of fetal movement, absent fetal heart sounds, and severe nausea and vomiting are common. Passage of grapelike molar tissue suggests the diagnosis, and histologic examination confirms it. Pelvic ultrasonography, although not infallible, is helpful in diagnosis.
Human chorionic gonadotrophin (hCG) is produced by the proliferated trophoblastic tissue, and high serum levels of the subunit of hCG (-hCG) aid in the diagnosis of a gestational trophoblastic disease.
Complications of a partial or complete mole include intrauterine infection and septicemia, hemorrhage, toxemia, and development of persistent gestational trophoblastic disease. Placental site trophoblastic tumor, because of its intramural location, tends to cause bleeding; it may infiltrate adjacent tissues and occasionally metastasizes to distant sites. Choriocarcinoma, which is highly malignant, metastasizes early and widely via venous and lymphatic systems.
Updated on: Mar. 24, 2010
Beyond Morning Sickness 
The Proving Grounds