A hydatidiform mole is a rare mass or growth that forms inside the uterus at the beginning of a pregnancy.

See also: Choriocarcinoma

A hydatidiform mole results from over-production of the tissue that is supposed to develop into the placenta. The placenta normally feeds a fetus during pregnancy. In this condition, the tissues develop into an abnormal growth, called a mass. Often, there is no fetus at all.

The cause is not completely understood. Potential causes may include defects in the egg, problems within the uterus, or nutritional deficiencies. Women under 20 or over 40 years of age have a higher risk. Other risk factors may include diets low in protein, folic acid, and carotene.

• Vaginal bleeding in pregnancy during the first trimester
• Nausea and vomiting, may be severe enough to require a hospital stay
• Abnormal growth in the size of the uterus for the stage of the pregnancy
  • Excessive growth in about 50% of cases
  • Smaller-than-expected growth in about 33% of cases
• Symptoms of hyperthyroidism
  • Rapid heart rate
  • Restlessness, nervousness
  • Heat intolerance
  • Unexplained weight loss
  • Loose stools
  • Trembling hands
  • Skin warmer and more moist than usual
• Symptoms similar to preeclampsia that occur in the 1st trimester or early 2nd trimester. (This almost always indicates hydatidiform mole, because preeclampsia is extremely rare this early in normal pregnancies.)
  • High blood pressure
  • Swelling in feet, ankles, legs
  • Proteinuria

A pelvic examination may show signs similar to a normal pregnancy, but the uterine size may be abnormal and fetal heart sounds are absent. There may be some vaginal bleeding.

Tests may include:

• Serum HCG
• Ultrasound of the pelvis
• Chest x-ray
• Abdominal CT or MRI

This disease may also affect the results of the following tests:

• Transvaginal ultrasound
• HCG (quantitative)