What Is The Reason For Molar Pregnancy?

A molar pregnancy is a condition that occurs as a rare complication of pregnancy. It is caused due to an abnormal growth of trophoblasts- the cells that grow and become placenta.

What Is The Reason For Molar Pregnancy?

The reason for molar pregnancy is an improperly fertilized ovum or egg. There are 23 sets/pairs of chromosomes in humans, normally. Out of the two chromosomes in every pair, one chromosome comes from the mother while the other comes from the father.

In case of a complete molar pregnancy, one or two sperms fertilize a vacant ovum. As a result, all the genetic information is given by the father. In this case, the maternal chromosomes are inactivated or lost and the paternal chromosomes are replicated.

In case of a partial molar pregnancy, the maternal chromosomes are available, but the father supplies two groups of chromosomes. Consequently, there are 69 chromosomes in the embryo when there should only be 46. This occurs when two sperms fertilize a single egg. Thus, there is an extra set of the father’s genetic material.

Thus, you can see that the reason for molar pregnancy is an improperly or abnormally fertilized egg. There is an imbalance in the number of chromosomes contributed by both mother and father. This kind of a fertilized egg will not be able to survive. There is usually a miscarriage in the early weeks of pregnancy. Even if the fetus survives, there will be a restricted growth and if at all the pregnancy reaches full term, the baby born out of such pregnancy will most probably be abnormal. Very, very rarely a normal baby is born in case of a molar pregnancy.

Symptoms Of Molar Pregnancy

At first, a molar pregnancy may appear anything like a normal pregnancy. However, it causes some specific signs and symptoms

  • You may experience vaginal bleeding
  • There may be nausea and vomiting
  • Grape- like Cysts passing through vagina
  • Pelvic pain or a pressure

On further evaluation by your doctor, he may find-

  • A fast-uterine growth, which does not correspond to the week of gestation
  • Hypertension (high blood pressure)
  • Preeclampsia- there is proteinuria along with a hypertension, which happens beyond 20 weeks of pregnancy
  • Anemia
  • Cysts in the ovaries
  • Hyperthyroidism

Risk Factors For Molar Pregnancy

Age of the mother-

Those women who conceive a pregnancy before 20 or after 35 years of age are more exposed to develop a molar pregnancy.


Those with a history of a previous molar pregnancy are more exposed to develop a molar pregnancy when they are pregnant the next time

Complications Of A Molar Pregnancy

Molar pregnancy can cause serious complications. This may even include a very rare type of cancer.

  • After the removal of the molar pregnancy, some molar tissue may still remain inside the uterus and keep growing. This condition is known as persistent GTN- Gestational Trophoblastic Neoplasia. This is seen more in complete than partial type of molar pregnancy.
  • There may be a presence of HCG- Human Chorionic Gonadotropin hormone- in the body, even after the molar pregnancy is removed. This may be one of the signs of GTN
    In some other cases, the molar pregnancy may root inside the uterus wall which may cause vaginal bleeding.
  • Very rarely, a cancerous type of GTN known as choriocarcinoma, can develop and may even spread to other organs and body parts. This is more likely to be seen in complete molar pregnancy than in the partial type
  • Persistent GTN can be efficiently treated with the help of chemotherapy
  • Choriocarcinoma can be efficiently treated with the help of different cancer drugs
  • Hysterectomy remains yet another option for the treatment of both conditions

A molar pregnancy is a complication of pregnancy, which is quite occasional. It is caused due to an uncharacteristic fertilization of an egg. It needs to be treated promptly and efficiently, to avoid any complications.

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