Molar Pregnancy: Everything You Need To Know About Molar Pregnancy

Molar Pregnancy: Everything You Need To Know About Molar Pregnancy

A molar pregnancy is a placenta abnormality, caused by a problem when the egg and sperm participate in the fertilization cycle.   Often known as a gestational trophoblastic disease (GTD), hydatidiform mole, or simply called a “mole,” this is a rare condition that occurs in 1 out of 1,000 pregnancies.

A vesicular mole is an unusual form of pregnancy in which the uterus is implanted by a non-viable fertilized egg and will fail to come to term.

Because of its superficial resemblance to hydrated cyst it is named as a hydatidiform mole. It is known as a benign neoplasm of the chorion with malignant possibilities.

The placenta grows inside of your uterus during a healthy pregnancy. It feeds your baby by the umbilical cord. With a molar pregnancy, the tissue becomes an abnormal mass or tumour in the uterus, instead of a placenta.

Incidence Of Molar Pregnancy

Hydatidiform mole

It is common in Oriental countries the Philippines, China, Indonesia, Japan, India, Central and Latin America and Africa the highest incidence is in Philippines being1 in 80 pregnancies and Lowest in European countries 1 in 752 and USA Bing about 1 in 2000 the incidence in India is about 1in 400.


There are two types — partial and complete.

 A partial molar pregnancy is one, in the case when both the placenta and embryo (fertilized egg) are abnormal.  A fetus may also be formed, but the fetus cannot survive, and usually gets miscarried early in pregnancy.

There is an irregular placenta in a complete molar pregnancy but no embryo. The placental tissue is irregular and swollen incomplete molar pregnancy and appears to form fluid-filled cysts. There is also no fetal tissue growth.


The cause is not definitely known but it appears to be related to the ovular Defects as it sometimes affects one ovum of a twin pregnancy.

An abnormally fertilised egg causes a molar pregnancy. Human cells normally contain 23 chromosomal pairs. One chromosome in each pair comes from the father, and the other comes from the mother.

In a complete molar pregnancy, one or two sperms fertilize an empty egg, and all the genetic material comes from the father, In this case, the chromosomes are missing or inactivated from the mother’s egg, and the chromosomes of the father are duplicated.

The mother’s chromosomes remain in a partial or incomplete molar pregnancy but the father has two sets of chromosomes. As a result, the embryo has 69 instead of 46 chromosomes. This most often happens when two sperms fertilize an egg which results in an extra copy of the genetic material of the father.

Risk factors

About 1 in every 1,000 pregnancies are diagnosed as a molar pregnancy. Various factors contribute to molar pregnancy including:

Maternal age. Its prevalence is highest in teenage pregnancies and in those women over 35 years of age. 

Faulty nutrition caused by inadequate intake of protein animal fat may play a role in its occurrence in Oriental countries. Low dietary intake of carotene is associated with increased risk. 

Previous molar pregnancy If you have been pregnant with one molar, you’re more likely to have another. On average, a repeat molar pregnancy occurs in 1 in every 100 women.


Age and Parity; it is prevalent amongst aged elderly patients with high parity. The patient gives amenorrhea history 8 to 12 weeks with initial characteristics suggestive of normal pregnancy but subsequently, e presents the following manifestations that are often confused with abortion.

1) Vaginal bleeding: Vaginal bleeding is the commonest symptoms (90%). Often the symptoms look like an incomplete or threatened abortion. the blood may be mixed with gelatinous fluid from ruptured cyst giving the appearance of discharge white currant in red currant juice.

2)Lower abdominal pain: Lower abdominal pain of varying degree due to

  • Stretching of the uterus
  •  concealed hemorrhage
  • Invasive mole perforate the uterus rarely
  • Infection or uterine contraction to expel out the contents.

3)  The patient becomes sick without any Apparent reason

4) Vomiting of pregnancy become successive to the stage of hyperemesis in 15% cases it is probably related to excess gonadotropin

5) Breathlessness due to pulmonary Embolization of the trophoblastic cells.

6) tremors or tachycardia present Occasionally.

7) Passing of grapes like vesicles through the vagina is Diagnostic of vesicular mole.  approximately 50% of cases the mole is not suspected until it is expelled in part or whole. 

Signs Of Hydatidiform mole

If you have any signs or symptoms of a hydatidiform mole, consult with your doctor or health care provider. He or she may detect other signs of molar  pregnancy such as:

  • Sudden uterine growth — the uterus becomes too large for the stage of pregnancy
  • High blood pressure
  • Preeclampsia — a condition after 20 weeks of pregnancy that induces high blood pressure and protein in the urine
  • Ovarian cysts
  • Anaemia
  • Overactive thyroid (hyperthyroidism)


If your doctor suspects a molar pregnancy, he or she will recommend blood tests including one to measure the level of human chorionic gonadotropin (HCG) in your blood — a pregnancy hormone. He or she is also going to recommend an ultrasound. High-frequency sound waves are directed at the tissues in the abdominal and pelvic area using a standard ultrasound. However, the uterus and Fallopian tubes are closer to the vagina than to the abdominal surface during early pregnancy, so the ultrasound can be done through a wand-like device placed in your vagina.

An ultrasound of a complete molar pregnancy — detectable as early as eight or nine weeks of pregnancy — may show:

  • No embryo or fetus
  • No amniotic fluid
  • A thick cystic placenta nearly filling the uterus
  • Ovarian cysts

An ultrasound of partial molar pregnancy may show:

  • A growth-restricted fetus
  • Low amniotic fluid
  • A thick cystic placenta

If a molar pregnancy is suspected by your doctor, he or she may test for other medical issues including:

  • Preeclampsia
  • Hyperthyroidism
  • Anaemia

Investigation; the doctor may suggest for the following test

Full blood count with blood group

Liver function test

Kidney function test

Thyroid function test

Ultrasound of liver spleen kidneys also carried out.

A plain x-ray of abdomen; negative fetal shadow may be helpful if uterus size is more than 16weeks.

X-ray of chest; must be carried out as a routine to rule out pulmonary embolisation. 


Molar pregnancy live fetus

Immediate complications;

1) Bleeding and shock: The bleeding is due to:

A) separation of vesicles from its attachment to decidua.

B)excessive intraperitoneal bleeding which may be the first indication  of perforating mole

2) Sepsis :

Increased risk of sepsis because there is no protective membrane that can penetrate the veginal organism into the uterine cavity. 

3) Pre-eclampsia

Pre-eclampsia typically starts with a woman whose blood pressure was elevated and shows protein in urine at 20 weeks of pregnancy. It can lead to serious problems, including fatal ones, for both mother and baby.

4) Molar tissue can remain, and continue to grow after a molar pregnancy has been removed. This is called recurrent, trophoblastic gestational neoplasia (GTN).

This happens in around 15 to 20% of complete molar pregnancies and up to 5% of partial molar pregnancies. One indicator of persistent GTN is a high level of human chorionic gonadotropin (HCG)—a pregnancy hormone — after removal of the molar pregnancy.

In some cases, an invasive hydatidiform mole penetrates deep into the uterine wall’s middle layer and causes vaginal bleeding. Recurrent GTN can almost always be treated with success, most often with chemotherapy. Another method for the treatment is uterine removal (hysterectomy).

A cancerous GTN type known as choriocarcinoma rarely grows and spreads to other organs. Multiple cancer medications typically treat choriocarcinoma successfully. This condition is more likely to present a complete molar pregnancy than a partial molar pregnancy.


A pregnancy with molars can not continue as a regular, viable pregnancy. The irregular placental tissue must be removed to avoid complications. Treatment consists usually of one or more of the following steps:

Dilation and curettage (D&C): The doctor must remove the molar tissue from your uterus, using a procedure called dilation and curettage (D&C), to treat a molar pregnancy. A D&C is usually performed in the hospital as an outpatient treatment. You must receive a local or general anaesthetic during the operation and be positioned with your legs in stirrups on the operating room table on your back. As in a pelvic exam, your doctor inserts a speculum into your vagina to see your cervix. He or she will then dilate your cervix with a vacuum device and remove the uterine tissue.

Hysterectomy: Rarely is it possible to remove the uterus (hysterectomy) if there is an increased risk of gestational trophoblastic neoplasia (GTN) and there is no intention for future pregnancies?

The doctor may decide to remove uterus incase of severe uncontrolled vaginal bleeding which is very rare.

HCG monitoring: Once the molar tissue is removed, your doctor will repeat your HCG level measurements until it is normal again. You may need extra care if you happen to have HCG in your blood.

 Once the molar pregnancy treatment is complete, your doctor may continue to monitor your HCG levels for six months to a year to ensure that no residual molar tissue is present.

 Because HCG levels during pregnancy also increase during a normal pregnancy, your doctor may recommend that you wait six to 12 months before trying to get pregnant again. During this time your doctor will be recommending a reliable form of birth control.


If you have had a molar pregnancy, check with your doctor or pregnancy care provider before you re-conceive. He or she may recommend waiting to get pregnant for six months to a year.

The risk of recurrence is minimal, but higher than that of women with no history of molar pregnancy beforehand. Your doctor may do early ultrasounds during any subsequent pregnancies to monitor your condition and provide reassurance of normal development.

Your doctor may also address prenatal genetic testing that can be used to treat with molars pregnancy.

How will I feel emotionally after a vesicular mole?

Although removing a molar pregnancy does not end a developing child, it is still a loss. Even when an embryo is present it has no chance to develop into a child.

Many women find that after the discovery and excitement of being pregnant, they are struggling with a molar pregnancy. Dreams, hopes, and wishes are all cancelled at once; it is still a major loss.

For all involved, there will have to be a healing time, and the grief will be felt. Recognize that people can try to comfort you with comments like, “It wasn’t a baby at least.”

That doesn’t help, but at least they know they’re trying. Let them exactly what it takes you. What further separates this type of loss from a “natural miscarriage” or death is the ongoing worry about the mother’s health.

Make sure you stick with your subsequent appointments. Support groups and counselling can be helpful.

Will this happen again?

If you had an uncomplicated molar pregnancy, the chance of another molar pregnancy is about 1-2%.

Genetic counselling is useful for some couples before conceiving again.


Dr Sufia Shaikh

Myself Dr Sufia, Doctor by profession speciality in Woman's Health with an experience more than 14 years. I do blogging on Pregnancy & Parenting Tips.

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