Definition

Molar pregnancy, also known as a hydatidiform mole or grape pregnancy, is a rare complication of pregnancy in which the placenta does not develop normally. Instead, the placenta forms abnormal growths that resemble a cluster of grapes.

In cases of molar pregnancy, the fetus often does not develop at all, and only the abnormal placental tissue grows. This condition is difficult to detect early on because it mimics a normal pregnancy, making regular prenatal check-ups crucial for early detection.

Molar pregnancy is one type of gestational trophoblastic disease (GTD), where a tumor forms in the uterus during pregnancy. This tumor is filled with fluid and appears like a cluster of grapes. The tumor cannot support the embryo's needs, leading to a miscarriage. The cluster is referred to as a hydatidiform lump.

There are two types of molar pregnancy: complete and partial. In a complete molar pregnancy, the abnormal placental tissue grows without any fetal development. The tumor can produce the pregnancy hormone hCG, which is also produced by a healthy placenta during a normal pregnancy.

In a partial molar pregnancy, abnormal placental tissue grows alongside a developing fetus. However, the fetus is usually malformed and cannot survive due to the tumor obstructing its growth.

Causes

Molar pregnancy occurs due to genetic errors during the fertilization of an egg by sperm or an abnormal fertilization process. In a healthy pregnancy, the placenta forms to support the embryo's development. In a molar pregnancy, the placenta does not develop normally and instead forms a tumor in the uterus. Consequently, the fetus rarely develops in such conditions.

Risk Factor

• Age: Women who become pregnant before age 20 or after age 40 have a higher risk of molar pregnancy.
• History of Molar Pregnancy: Women who have had a molar pregnancy before are at higher risk of experiencing it again in subsequent pregnancies.
• History of Miscarriage: Women who have had two or more miscarriages are at a higher risk of molar pregnancy in future pregnancies compared to those who have never miscarried.

Symptoms

Common symptoms of molar pregnancy include:

• Vaginal bleeding during the first trimester
• Severe nausea and vomiting
• Preeclampsia (extremely high blood pressure)
• Elevated levels of the hormone hCG
• Rapid increase in abdominal size compared to a normal pregnancy
• Absence of fetal heartbeat or movement
• A grape-shaped cyst comes out from the vagina

Diagnosis

Ante-Natal Care (ANC)

Diagnosing a molar pregnancy can be challenging, especially in early pregnancy. It is usually detected during routine prenatal exams.

Ultrasound Examination

An obstetrician will diagnose a molar pregnancy through an ultrasound, which uses sound waves to create an image of the uterus.

During an ultrasound at around 8 or 9 weeks of pregnancy, the following signs may indicate a molar pregnancy:

• In a complete molar pregnancy:
• No fetus in the uterus
• No amniotic fluid
• Presence of ovarian cysts
• Thickened placenta filling the uterus
• Placenta resembling a cluster of grapes
• In a partial molar pregnancy:
• Slowed fetal growth
• Low amniotic fluid
• Thickened placenta

Laboratory Tests

The obstetrician may recommend blood tests to measure the mother's hCG levels.

Other tests that may help determine the condition include:

• Pelvic exam
• Abdominal ultrasound
• Chest X-ray
• CT or MRI of the abdomen
• Complete blood count and clotting tests
• Kidney and liver function tests

Management

Most cases of molar pregnancy do not require special treatment, as the grape-like cysts will spontaneously pass from the uterus through the birth canal.

Curettage

Some women may need specialized treatment to remove the molar pregnancy. This involves dilating the cervix and performing a curettage, where a tool is used to remove the abnormal tissue from the uterus through suction.

Hysterectomy

In certain cases, a hysterectomy (surgical removal of the uterus) may be necessary to treat a molar pregnancy. The doctor will ensure that all tumor cells have been removed through various tests. Typically, these cells disappear within a few months, but further treatment may be needed in some cases.

hCG Level Monitoring

The doctor will recommend regular blood and urine tests to monitor hCG levels to ensure they return to normal after the abnormal tissue has been removed. If hCG levels remain elevated, it indicates that some abnormal cells are still present in the uterus. This monitoring is conducted for 6 months to a year after the molar pregnancy.

Postpone Pregnancy

Patients are also advised to avoid becoming pregnant for one year after experiencing a molar pregnancy. The obstetrician may suggest contraceptive methods to prevent pregnancy during this period.

Complications

In general, parts of the molar pregnancy may remain in the uterus after the pregnancy or treatment ends. In some cases, GTD can progress to conditions like choriocarcinoma, a cancer that forms in the uterus and can spread to other areas. To check if the cancer has spread to the lungs, the obstetrician may recommend a chest X-ray. If choriocarcinoma is detected or has spread, specialized cancer treatment, such as chemotherapy, will be necessary.

Other potential complications include:

• Preeclampsia
• Thyroid hormone imbalances
• Persistent or recurrent molar pregnancy
• Blood infection (sepsis) and uterine infection
• Complications from surgery to remove the molar pregnancy, such as excessive bleeding and anesthesia side effects

For additional information regarding pre-eclampsia, click this link: Pre-Eclamployment - Definition, Cause, Symptom, and Treatment.

Prevention

Currently, there is no way to prevent a molar pregnancy. If a woman has a history of molar pregnancy, she can reduce the risk of complications by postponing pregnancy for one year after the previous molar pregnancy.

Doctors will also monitor hCG levels monthly for up to a year to ensure that no molar pregnancy tissue remains in the uterus. Consult your doctor if you plan to conceive again.

Doctors will advise delaying pregnancy for 6 months to a year. To prevent pregnancy, women can use contraceptive methods other than intrauterine devices (IUDs). The risk of recurrence is low, but it is higher in women with a history of molar pregnancy.

Doctors will conduct evaluations and provide necessary treatment to prevent complications.

When to See a Doctor?

Contact your doctor if you experience:

• Vaginal bleeding
• Severe nausea and vomiting
• An unusually large abdomen for your pregnancy stage
• A grape-shaped cyst protruding from the vagina

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