A molar pregnancy is a benign uterine growth that occurs when a sperm fertilizes an egg empty of genetic information. Though the growth itself is benign, complications can arise, and the growth should be treated quickly. Molar pregnancies occur in about one out of every 1,000 to 1,500 pregnancies, and can also be called mole, hydatidiform mole, or gestational trophoblastic disease.
There are two types of molar pregnancy: complete and partial. Neither is a viable pregnancy.
A complete molar pregnancy is caused by an egg with no nucleus being fertilized. The fertilized egg grows, but cannot become a baby because genetic information is missing.
A partial molar pregnancy results when two sperm fertilize an egg, resulting in too many chromosomes being present. The molar growth will outpace the growth of any fetal tissue.
A past molar pregnancy
Maternal age (risk increases with age after 35)
History of miscarriage
Diet low in Vitamin A (suspected)
If you have a molar pregnancy, you will feel pregnant, because pregnancy hormones are present even if fetal tissue is not. However, there are another set of symptoms that are rarely part of a healthy pregnancy. If you are having these symptoms, check in with your doctor; common tests done during early pregnancy (HCG levels, pelvic ultrasound) will let your doctor know if there is the possibility of a molar pregnancy.
The uterus is large for the age of pregnancy
Grape-shaped tissue discharge (cystic placenta)
Extreme morning sickness
Symptoms of hyperthyroidism (fast heart rate, nervousness, heat intolerance)
Pelvic pressure or fullness
Swollen ovaries/ovarian cysts
Preeclampsia-like symptoms as early as the first or second trimester (high blood pressure, swelling)
Molar pregnancies can be detected as early as 8 or 9 weeks. Moles will usually result in late "missed" miscarriages if not diagnosed and treated early. Your doctor will be looking for:
Large and cystic placenta on ultrasound
No or low amniotic fluid on ultrasound
No fetus (complete mole) or growth-restricted fetal tissue (partial mole)
- Unusually high HCG levels
A dilation and curettage (D&C) or vacuum aspiration will be done as soon as possible after the molar pregnancy is discovered. It is very important that all of the growth be removed because any that is left will continue growing (trophoblastic disease). For 6-12 months your doctor will monitor your HCG levels to confirm that there is no further molar growth. If there is additional growth, removal is necessary.
While over 80 percent of molar pregnancies or "moles" are successfully treated upon removal, some can become invasive moles. Invasive moles grow into the wall of the uterus and can cause bleeding, among other possible complications.
Rarely, moles develop into a form of cancer known as choriocarcinoma. This cancer is successfully treated with common cancer treatments.
Molar pregnancies are a pregnancy loss; grief is to expected. If you experience a molar pregnancy, it is important to allow yourself to go through the grieving process. A counselor specializing in pregnancy loss should be consulted if needed or desired.