Diagnosis

If your doctor suspects a molar pregnancy, he or she will order blood tests, including one to measure the level of human chorionic gonadotropin (HCG) — a pregnancy hormone — in your blood. He or she will also recommend an ultrasound.

With a standard ultrasound, high-frequency sound waves are directed at the tissues in the abdominal and pelvic area. During early pregnancy, however, the uterus and fallopian tubes are closer to the vagina than to the abdominal surface, so the ultrasound may be done through a wandlike device placed in your vagina.

An ultrasound of a complete molar pregnancy — which can be detected as early as eight or nine weeks of pregnancy — may show:

• No embryo or fetus
• No amniotic fluid
• A thick cystic placenta nearly filling the uterus
• Ovarian cysts

An ultrasound of a partial molar pregnancy may show:

• A fetus that's unexpectedly small for gestational age
• Low amniotic fluid
• Placenta that appears abnormal

If your health care provider detects a molar pregnancy, he or she may check for other medical problems, including:

• Preeclampsia
• Hyperthyroidism
• Anemia