What is Molar Pregnancy?

What is Molar Pregnancy?

Not every positive pregnancy test is a sign of a live, healthy baby. Molar pregnancy is an unhealthy type of pregnancy. Molar pregnancy is defined as “a mother carrying a thousand babies” in the writings of Hippocrates. It is also known as “grape pregnancy” among the public. Due to the presence of a genetically defective embryo with an abnormal chromosome arrangement, the uterus is filled with abundant, grape-shaped, swollen vesicles, which are filled with fluid. The incidence has been reported as 1 in 1000-2000 pregnancies. In those who have had a molar pregnancy before, the risk of having a molar pregnancy again increases by 10 times and rises to 1%.

HOW DOES MOLAR PREGNANCY OCCUR?

In a healthy pregnancy, during fertilization, the egg cell takes in a single sperm and closes the entrance gates. Thus, the embryo, which receives 23 chromosomes from the mother’s egg cell and 23 chromosomes from the father’s sperm, consists of 46 chromosomes. However, in a molar pregnancy, two sperm enter the egg cell at the same time and embryos with strange chromosome numbers are formed.

WHAT ARE THE TYPES OF MOLAR PREGNANCY?

There are two types: Complete and partial moles.

The complete form is more common and is more dangerous, and can turn into cancer. If two sperms manage to enter the egg cell at the same time and the genetic information of these sperms, consisting of 23 chromosomes each, combine in the nucleus of the egg cell and cause the egg’s own genetic information to be destroyed, the embryo consists of 46 chromosomes. Even if the number of chromosomes is normal, this strange embryo, which has not received any genetic structure from the mother, produces an abnormal pregnancy product consisting of many swollen villi and no structures belonging to the fetus. This is called complete molar pregnancy.

If two sperms manage to enter the egg cell at the same time and the genetic information of these sperms, consisting of 23 chromosomes each, combine in the nucleus of the egg cell and do not cause the egg’s own genetic information to be destroyed, the embryo consists of 69 chromosomes. Although structures belonging to the fetus appear, this abnormal fetus is not compatible with life. Together, an abnormal pregnancy product occurs, again with numerous swollen villi. This is called a partial (partial) mole pregnancy.

A complete mole gives symptoms in the earlier stages of pregnancy. In a partial mole, since the fetus is already formed, diagnosis can sometimes be delayed until the 20th week.

In a partial mole, the fetus is triploid (69 chromosomes) and often results in intrauterine death.

WHAT ARE THE CAUSES OF MOLAR PREGNANCY?

  • Low socioeconomic status
  • Poor nutrition
  • Folic acid and carotene deficiency
  • Maternal age over 40
  • Maternal age under 20
  • Being of Far Eastern origin
  • Having had two or more molar pregnancies before
  • Having had more than one miscarriage in the past

WHAT ARE THE SYMPTOMS OF MOLAR PREGNANCY?

The first symptom is bleeding following a missed period. The amount of pregnancy test (B-HCG) in the blood is much higher than normal. Nausea and vomiting are more severe than normal. Although very rare, conditions such as large ovarian cysts (theca lutein), high blood pressure (preeclampsia), hyperthyroidism, and excessive hair growth (due to high testosterone) may occur. Some pregnant women may present with the complaint of “dropping a piece resembling a grape.” Partial moles may be milder than complete moles and may show symptoms at a later stage.

HOW IS MOLAR PREGNANCY DIAGNOSED?

Diagnosis is made with ultrasonography. A gestational sac is not seen in the uterus. Instead, swollen mole vesicles line up side by side, creating a “snowfall landscape”. The uterus may be measured larger than the gestational age on examination. A pregnancy test measured in the blood supports the diagnosis if the B-HCG value is over 100,000. Diagnosing a partial mole may not be as easy as a complete one, unfortunately. A gestational sac is usually present on ultrasound. If there is a fetus in the sac, it may be mistakenly thought to be a normal pregnancy. Therefore, a careful examination of the placenta is required to diagnose a partial mole. A complete molar pregnancy, if not intervened, usually ends with miscarriage by the 16th week of pregnancy. The partial type may continue for a longer period.

HOW IS MOLAR PREGNANCY TREATED?

After the diagnosis of molar pregnancy is made, the pregnancy should be terminated without delay by talking to the family. For this purpose, curettage is performed under general anesthesia. Before the evacuation, a chest X-ray is taken for possible cancer and metastasis research and the B-HCG value is monitored. The blood type is determined and if there is Rh incompatibility, Anti-Rh immunoglobulin (incompatibility injection) is applied. If bleeding is severe, a blood transfusion can be performed.

The probability of unwanted situations related to abortion during molar evacuation increases in relation to the size of the gestational age. The occurrence of unwanted situations, especially uterine injury, perforation; infection and bleeding, is directly related to the size of the gestational week. Therefore, early diagnosis of molar pregnancy is important.

In molar evacuation, unlike normal pregnancy evacuation, there is a risk of pulmonary embolism (blockage of the artery itself or one of its branches by a substance coming from the circulation) due to one of the trophoblasts passing into the blood vessels during the intervention. In addition, a dangerous condition called DIC (disseminated intravascular coagulation) may develop rarely after evacuation. The parts that come out during the evacuation are definitely sent for pathological examination.

For a woman with a molar pregnancy, if she has completed the number of children and is over 40 years old, hysterectomy (surgical removal of the uterus) is an appropriate treatment method. Hysterectomy significantly reduces the risk of developing cancer after a molar pregnancy, but does not completely eliminate it. Therefore, even if a hysterectomy is performed, follow-up continues in the same way.

HOW TO FOLLOW A MOLAR PREGNANCY?

Molar pregnancy can recur, so patients are closely monitored. During the follow-up period, the patient is prohibited from getting pregnant for 1 year. Birth control pills are started, intrauterine devices (IUDs) are not suitable. If pregnancy occurs during this period, it is not possible to distinguish whether the increased B-HCG is due to natural pregnancy or a possible recurrence. During follow-up, weekly measurements are made until the blood B-HCG levels drop to zero. When B-HCG is measured as zero three times, weekly follow-up is switched to monthly follow-up. Patients are monitored every month for 1 year. If everything is normal at the end of 1 year, the patient is allowed to get pregnant. The risk of having a second molar pregnancy after a molar pregnancy is 1%. Therefore, caution should be exercised when getting pregnant again.

IS MOLAR PREGNANCY DANGEROUS?

Molar pregnancy can develop into a type of tumor called Gestational Trophoblastic Neoplasia (GTN). GTN is a disease that can spread to other parts of the body (metastasis) or recur in the uterus. If the patient’s blood B-HCG levels do not decrease during follow-up, remain the same, or start to increase again after decreasing for a while, GTN may develop. GTN occurs in 50% of cases following a molar pregnancy, 25% following a miscarriage, and 25% following a normal pregnancy. It responds very well to chemotherapy. Otherwise, other treatments such as hysterectomy and intra-arterial chemotherapy may be required. The most commonly used chemotherapeutic agent is Methotrexate. In addition, agents such as Actinomycin-D, Etoposide, and 5-Fluorouracil can be used.