Molar pregnancy, also known as gestational trophoblastic disease (GTD), occurs when there is a development of abnormal cells called trophoblasts in the placenta. This condition is classified into two types. The first type is a complete molar pregnancy, where there is no fetus present, only a mass of abnormal cells in the uterus. The second type is a partial molar pregnancy, where a fetus does develop, but due to the presence of abnormal cells, it is not viable. It is estimated that approximately one in every 1,000 to 1,500 pregnancies is diagnosed as a molar pregnancy.
Symptoms of Molar Pregnancy
A molar pregnancy can often present symptoms similar to those of a normal, healthy pregnancy. Nausea, bloating, and vaginal bleeding are some common symptoms that a woman may experience with a molar pregnancy, which can also be observed in a healthy pregnancy. Typically, a molar pregnancy is detected during a routine ultrasound scan conducted between the 8th and 14th weeks of pregnancy. In some cases, if a woman has experienced a miscarriage, tests and scans performed after the miscarriage may reveal indications of a molar pregnancy. Additionally, other signs and symptoms that may be observed include:
Causes
A molar pregnancy occurs due to abnormalities in the fertilization process of the egg. There are two types of molar pregnancies:
1. Complete Molar Pregnancy: In this type, an “empty egg” or an egg with no genetic information is fertilized by one or two sperm, resulting in all of the genetic code being from the father. As a result, no fetus can develop. Instead, abnormal tissue resembling a cluster of grapes forms and fills the uterus.
2. Partial Molar Pregnancy: This type occurs when an egg is fertilized by two sperm, leading to the presence of 69 chromosomes instead of the normal 46. In this case, a fetus may begin to develop, but with severe defects.