Molar Pregnancy, medically termed as hydatidiform mole; is a rare complication of pregnancy or gestational trophoblastic disease (GTD) characterized by the abnormal growth of either the embryo or the trophoblasts (the cells that normally develop into the placenta) or both often leading to a loss of pregnancy in the early stages.

Also Read: Ectopic Pregnancy: Causes, Symptoms And Treatment

In a normal healthy pregnancy, the fertilized embryo usually attaches itself to the uterus where the placenta that grows inside the uterus nourishes the growing embryo through the umbilical cord. In case of a molar pregnancy, this placenta or the tissue becomes an abnormal mass or tumor and contains fluid-filled sacs or cysts. In rare cases, a molar pregnancy can also lead to health risk of the mother or transform into a rare type of cancer among other complications.
Molar pregnancy diagram


A molar pregnancy is usually categorized into two types:

Partial molar pregnancy - A pregnancy is said to be partial mole if the developing uterus has both placental tissue and abnormal fetal tissue that can never grow into a baby. In some cases, there may be formation of a fetus, but it is not able to survive, and is usually miscarried early in the pregnancy.

Complete molar pregnancy – A pregnancy is described as a complete mole if the uterus contains only abnormal placental tissue and does not have any sign of the growing embryo. It usually appears to be abnormal and swollen and full of fluid-filled cysts.


A molar pregnancy can happen to anyone and is unrelated to ethnicity or background. It usually happens due to abnormality of the DNA strands within a gene of a fertilized embryo. All human cells have 23 pairs of chromosomes, where one chromosome in each pair comes from the father, the other from the mother. And a healthy female contains hundreds and thousands of eggs depending upon the age, some of which does not mature or remain within the follicle, which are then removed from the body during monthly menstrual cycle.

But sometimes, if an immature or imperfect egg gets fertilized by a sperm, it often contains genes from only the father and not the mother causing a Molar Pregnancy. In such cases, the chromosomes from the mother's egg get lost or inactivated whereas the father's chromosomes get duplicated resulting in, the embryo having 69 chromosomes instead of 46. Molar pregnancy can also happen if a perfect and mature egg gets fertilized by an imperfect sperm or more than one sperm.

Risk Factors

Certain causative factors that increase the risk of molar pregnancy include:

Age: Although, it can happen to anyone, women older than age 35 or younger than age 20 are more likely to have a molar pregnancy.

Previous History Of Molar Pregnancy: Chances of molar pregnancy are more if you had a molar pregnancy in the past. Then again, you can also have a completely normal pregnancy even if you had a molar one in the past.

Health Conditions: A person suffering from infertility problems or having issues while conceiving is more prone to having molar pregnancy.

Previous Miscarriage: Even a miscarriage due to some other problem increases the chances of molar pregnancy.


Although the signs and symptoms of a molar pregnancy might just mimic the ones of a healthy pregnancy, but some of the characteristic different ones include:

  • Bright red or dark brown vaginal bleeding in the first trimester
  • Severe nausea and vomiting due to excessive hCG
  • Pelvic pressure or pain
  • Vaginal discharge looking like grapelike cysts

On suspecting molar pregnancy, consult a doctor immediately as he or she may detect other significant symptoms including:

  • Rapid growth of uterus
  • High blood pressure
  • Preeclampsia
  • Overactive thyroid gland
  • Ovarian cysts
  • Anemia

Diagnosis And Treatment

On noticing the above-mentioned signs and symptoms, do visit a gynecologist immediately, to get checked and treated at the earliest. The doctor usually does a pregnancy test to measure the level of human chorionic gonadotropin (HCG) hormone in the blood as in case of a molar pregnancy, the hCG hormone is quite high, above normal levels. The doctor may also conduct an ultrasound test to look inside the uterus for detecting any abnormalities. This ultrasound which is done trans-vaginally can detect an early molar pregnancy even in the 9th week. It usually detects, the absence of fetus or embryo, presence of ovarian cysts, absence of amniotic fluid and a thick cystic placenta nearly filling the uterine space.

Also Read: Pregnancy Test: What Is It And What To Expect?


A molar pregnancy can never grow into a normal healthy pregnancy and hence the abnormal tissue must be removed in order to avoid further complications for the mother. The doctor usually conducts either of the procedures for successful removal of a molar pregnancy. This includes:

  • Dilation and curettage, D&C (removal of the molar tissue from the uterus)
  • Hysterectomy (in case of increased risk of gestational trophoblastic neoplasia and the couple has no desire for future pregnancies, the entire uterus is removed)
  • Chemotherapy medications (to reduce the risk of cancer complications, medications are used after D&C)
  • RhoGAM (a person having Rh-negative blood group receives a medication to prevent complications related to developing antibodies)
  • Further blood tests and monitoring should be conducted to ensure that there is no molar tissue left behind in the womb to prevent regrowth of molar tissue or any cancerous condition.