What Is Molar Pregnancy? Is Hydatidiform Mole Linked to Cancer?

What Is Molar Pregnancy? Is Hydatidiform Mole Linked to Cancer?

Despite the happiness that pregnancy brings in a woman’s life, some rare complications can inflict the adverse effect. The effect is so much so that even after a miscarriage, the complication can wreak a devastating effect on woman’s health. We will be dealing with a rare but serious pregnancy issue that affects about 1 in every 1000 women.

Molar Pregnancy

Molar pregnancy often referred to as Hydatidiform Mole is a rare pregnancy complication. Molar pregnancy is basically a type of gestational trophoblastic disease that occurs when tissues that instead of normally developing into a fetus, turns into an abnormal growth. The condition is characterized by an unusual growth of trophoblasts, the cells which normally develop and form a major part of the placenta in pregnancy.

Molar pregnancy can be a scary thing as the growth inside is not an embryo but a chromosomal abnormality. The abnormal tissue needs to be treated right away as it can cause serious complications in some women.

Incidences of Molar Pregnancy

Molar pregnancy typically occurs in the first trimester. This condition affects 1 in 1000 pregnancies worldwide. According to some studies, the chance of recurrence is higher, especially in South Asia. In another Indian study which was conducted on 8,104 pregnant women, 37 were found to be molar, which translates to 4.56 per 1000 deliveries.

And most of the cases found in the study belonged to remote areas with low socio-economic and educational status.

What Causes Molar Pregnancy?

Molar pregnancies generally fall into two categories; partial and complete molar pregnancy. Both occur due to chromosomal abnormalities in the fertilized egg.

In partial molar pregnancy, the embryo gets one chromosome from the mother and two from the father. This can result in embryo having 69 chromosomes instead of normal 46.

In complete molar pregnancy, the egg that comes from mother does not have any genetic information, instead all the genetic information comes from the father. As a result, the fertilized egg does not develop into a fetus. However, it continues to grow as a mass or lump of abnormal tissue.

Rarely, it happens that twin pregnancy is affected by this condition. In such case, one fetus will be normal and the other would be molar.

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Signs and Symptoms of Molar Pregnancy

A molar pregnancy typically has the same signs and symptoms of a normal pregnancy such as morning sickness and missed periods. However, it can also have its own specific symptoms which include:

  • Vaginal bleeding that is dark brown and bright red in color
  • Uterus that is larger than normal
  • Severe nausea and vomiting
  • High blood pressure
  • Uncomfortable pressure on the pelvis or pain
  • Signs of hyperthyroidism such as nervousness and tiredness or irregular heartbeat

Many of the above signs can also indicate miscarriages. So any woman experiencing these symptoms should consult a gynecologist right away.

Risk Factors for Molar Pregnancy

There are several risk factors that have been linked to molar pregnancies. These include:

Diagnosis of molar pregnancy

As molar pregnancy mostly occurs in the first trimester, it can be detected during routine examination. Especially, it can be identified when heartbeat of the fetus is not detectable by 12 weeks. The doctor will usually conduct pelvic examination and blood tests to check the level of pregnancy hormones.
However, diagnosis of molar pregnancy typically relies on ultrasound. The ultrasound which uses high-frequency sound waves to create pictures of the womb may reveal:

The doctor may also conduct tests for preeclampsia, anemia and hyperthyroidism.

Is molar pregnancy linked to cancer?

About 80 percent of hydatidiform mole or molar pregnancies are benign. However, pregnancy tissues can turn into cancer called choriocarcinoma, which is a type of gestational trophoblastic disease. This can happen when after removing molar pregnancy, the tissue remains keeps growing.

More than half of the cases of choriocarcinoma are due to molar pregnancy. Choriocarcinoma can also occur after early pregnancy miscarriage or after ectopic pregnancy. However, women who get cancer after failed pregnancy can be treated successfully.

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How molar pregnancy is treated?

If you have molar pregnancy, rest assured, it will not lead to successful childbirth. Without delay, the abnormal tissue has to be removed in order to prevent serious complications. Basically, the treatment is performed through following methods:

  1. Dilation and curettage – This is typically an outpatient procedure and you could be discharged from the hospital on the same day. You will first get a local anesthesia and the doctor will insert a device called a speculum into the vagina and dilate the cervix. The tissue inside will then be removed via vacuum suction.
  2. Hysterectomy – Some women with molar pregnancy might decide to have removed the entire uterus, also known as a hysterectomy. After this operation, these women won’t be able to become pregnant again. So it is important to consult the doctor before this surgery, especially if you want children in future.

There is a small chance that after gestational trophoblastic disease, molar pregnancy will turn into cancer. But if detected, it can be successfully treated with chemotherapy.

Can a woman with molar pregnancy become pregnant in future?

Even if the molar pregnancy turns into a trophoblastic disease or choriocarcinoma, it doesn’t prevent a woman from becoming pregnant in future. However, after the treatment, she may have to wait for up to 12 months before trying to conceive again. This is because the doctor will make sure that her HCG (human chorionic gonadotropin) hormone levels return to normal.

Increased HCG levels (a sign of pregnancy) might be a sign of invasive moles or choriocarcinoma, so waiting for 6 months or so would let the doctor distinguish between pregnancy and choriocarcinoma.

Molar pregnancy can also recur in future; the chances of returning are 1 out of 100. So if you are just recently been treated for molar pregnancy, make sure you follow-up the routine examination to rule out the recurrence.