What’s a Molar Pregnancy?

By OBGYN and fertility expert Dr. Kenosha Gleaton

Did you know that an empty egg can be fertilized? It doesn’t happen very often, but the result is a large mass in the uterus that shows up as a positive on a pregnancy test. Molar pregnancies occur about once out of every 1,000 pregnancies, and while rare, they can be dangerous and very upsetting for couples trying to get pregnant. [1] Let’s talk more about what molar pregnancies really are. 

What’s a Molar Pregnancy?

Also called gestational trophoblastic disease (GTD), a molar pregnancy is a rare condition that occurs due to genetic error during fertilization (when the sperm and egg meet). This leads to abnormal tissue growth in the uterus and eventually a molar pregnancy. The shorter answer: cells that should have formed into a placenta form a large mass or tumor in the uterus.

Types of Molar Pregnancies: Complete vs Partial

There are two types of molar pregnancies: 

• Complete
• Partial 

A complete molar pregnancy means there is no embryo present, and only placental parts have formed due to sperm fertilizing an empty egg. While hCG may have been detected (AKA a positive pregnancy test), this is due to the placenta producing hormones, when there is in fact no fetus.

A partial molar pregnancy occurs when the mass contains the abnormal tumor cells and an embryo. In partial molar pregnancies, the embryo will eventually be overcome by the growing mass and have severe birth defects. 

Signs of a Molar Pregnancy

Some symptoms common to molar pregnancies include:

• Severe nausea or vomiting (Shop Anti-Nausea Gummies)
• Vaginal spotting or bleeding 
• Early preeclampsia
• Increased hCG levels
• Absence of fetal movement or heartbeat

Risk Factors for a Molar Pregnancy

Developing a molar pregnancy is a rare occurrence, but you may be at a higher risk if you:

• Are over the age of 40
• Have a history of miscarriage
• Have had a previous molar pregnancy
• Are prone to developing uterine or vaginal cysts

How to Manage a Molar Pregnancy

Unfortunately, molar pregnancies aren’t viable, and the mole will need to be removed. Some pregnancies will spontaneously end, in which case you can expect grape-like tissue to come from the vagina. If the mole doesn’t expel on it’s own, medication or surgery may be used.

Follow up procedures to monitor hCG levels may occur for a few months, to ensure the mole has been removed completely.  

Healing for a Molar Pregnancy

Ending a molar pregnancy doesn’t mean you’re terminating a developing child, but it is still a difficult loss. It’s important to surround yourself with family and friends as you heal and grieve.

It’s encouraged that women don’t try to get pregnant within a year of a molar pregnancy, and the use of intrauterine birth control is discouraged. 

What Does a Molar Pregnancy Mean for Future Pregnancies?

Experiencing GTD puts you at a small risk of developing another molar pregnancy, but only around one to two percent. Genetic counseling may be helpful before attempting to conceive again. Learn more about fertility and trying to conceive on the Natalist blog. 

Key Takeaways

• Molar pregnancies, also called gestational trophoblastic disease (GTD), refer to a mole or tumor growth in the uterus due to an error during fertilization.
• Molar pregnancies can be complete or partial, meaning there could be an embryo growing with the tumor, or no embryo at all.
• Treating a molar pregnancy means using medication or surgery to get rid of the mole and will likely require a few months of follow-up appointments.

Sources:

1.  Soper, John T. MD. Gestational Trophoblastic Disease: Current Evaluation and Management. Obstetrics & Gynecology 137(2):p 355-370, February 2021. | DOI: 10.1097/AOG.0000000000004240