Molar pregnancy, also called hydatidiform mole, is a condition that results in the formation of a mass in the uterus in early pregnancy. The growth arises from the tissues that normally give rise to the placenta.
The placenta is the tissue that connects the uterus of the mother with the umbilical cord of the fetus. In molar pregnancy, this tissue proliferates abnormally resulting in the formation of a mass in the uterus. The tissue is called trophoblastic tissue and therefore molar pregnancy is a type of gestational trophoblastic disease (GTD).
A normal human cell contains 23 pairs of chromosomes, one set which comes from the father and one from the mother. However, in molar pregnancy, the fertilized egg has either two sets of paternal genes and none from the mother, or two sets from the father and one set from the mother. Accordingly, there are two types of molar pregnancy:
• Partial molar pregnancy: The fertilized egg contains two sets of paternal genes and one from the mother. This results in the formation of an abnormal fetus and some placental tissue.
• Complete Molar Pregnancy: The fertilized egg contains only two sets of paternal genes. There is no fetus, but shows the presence of an abnormal placental tissue.
Risk factors associated with molar pregnancy are:
• Age above 35 years or younger than 16 years
• Previous history of miscarriage and molar pregnancy
The most common signs and symptoms of molar pregnancy include vaginal bleeding, pelvic discomfort, severe nausea and vomiting, and passage of grape-like cysts.
Molar pregnancy can lead to serious complications including a rare form of cancer which is known as choriocarcinoma. However, this cancer is completely curable.
Treatment of molar pregnancy includes removal of the molar tissue by evacuation of the uterus. Surgical removal of the uterus may be necessary in some cases.