Pregnancy complications are full of complex and confusing terms molar pregnancy is one of them. Molar pregnancies don t have anything to do with your molar teeth and they are very rare. They affect about one in every 1,200 pregnancies and usually during the early stages.
What is a molar pregnancy?
Simply put, a molar pregnancy (its medical name is a Hydatidiform Mole) is an unsuccessful pregnancy. In a molar pregnancy the placenta grows rapidly and abnormally and forms a number of cysts (or moles) that nestle into the uterus.
A miscarriage in the first trimester is the most common way of a molar pregnancy being discovered. There are two types of molar pregnancies:
1. Complete molar pregnancies
In a complete molar pregnancy, the fertilised egg has no chromosomes from the mother but a duplicated set of chromosomes from the father. This abnormal combination prevents an embryo or foetus from forming altogether. Instead, a cluster of cysts forms as the placenta.
2. Partial molar pregnancies
Partial molar pregnancies are more common than complete molar pregnancies. In a partial molar pregnancy, a foetus will begin to develop but it doesn't have the required genetic make-up to survive. Usually, the fertilised egg in a partial molar pregnancy has a single set of chromosomes from the mother but a duplicated set from the father's sperm.
How does a molar pregnancy happen?
A molar pregnancy happens when:
- A sperm fertilises an egg
- The wrong number of chromosomes combine
- There are abnormalities in the cells that grow to form the placenta
Symptoms of a molar pregnancy
In a molar pregnancy, you will experience a number of regular pregnancy symptoms such as morning sickness and sore breasts. This is because, despite the abnormal development of the placenta, it continues to make the pregnancy hormone hCG which causes these symptoms. An abnormal placenta in a Molar Pregnancy will actually usually make higher amounts of hCG, than it would normally.
At some point you will also begin to notice some bleeding. This on its own doesn t mean you have a molar pregnancy, but you should check with your doctor or midwife if you have any concerns, even if only for peace of mind.
Other complications from a molar pregnancy
Unfortunately, there are a number of more serious complications that can surface as a result of a molar pregnancy.
One of the most serious complications is a very rare form of malignant cancer, called choriocarcinoma. This happens when the molar pregnancy cells grow deep into the uterus and lead to what's known as persistent gestational trophoblastic disease. This disease is also very rare but if it is particularly aggressive it can lead to choriocarcinoma when it spreads to other organs in the body. However, both diseases can be very successfully treated with chemotherapy.
Why did I develop a molar pregnancy?
Doctor's still don t know why a woman has a molar pregnancy. However, there are a few common traits of women who have been affected, including women who:
- Are under 18 or over 35
- Are of Asian or Mexican descent
- Follow a diet that provides insufficient levels of carotene (a form of vitamin A)
- Have had a molar pregnancy before
Treatment of molar pregnancies
The most effective way to treat a molar pregnancy is to clear out your uterus with a minor procedure called a dilatation and curettage, done under general anaesthetic.
If you experience heavy or excessive bleeding following your procedure, notify your doctor or midwife to rule out any further complications.Alternatively, your doctor may offer you a different, less invasive, way to treat your molar pregnancy. Medication can help your body shed the abnormal tissues by itself.
Last Published* December, 2022
*Please note that the published date may not be the same as the date that the content was created and that information above may have changed since.