Multifetal Pregnancy Reduction: Causes, Procedure and Risks

The prevalence of assisted reproductive technologies (ART) has contributed significantly to the increase in multifetal pregnancies. In order to avoid this to happen, all steps in the fertility process, such as the transferred embryo number, the effect of fertility drugs on ovulation, etc., are carefully monitored. However, when multiple pregnancies occur despite the precautions taken, all risks should be examined and options for continuation of pregnancy or fetal reduction should be evaluated.

What is Multifetal Pregnancy Reduction?

Multifetal pregnancy reduction (MFPR), also known as fetal or selective reduction, is a medical procedure performed to reduce one or more fetuses in a pregnancy. This procedure is usually done in the first trimester of pregnancy to increase the chances of a healthy pregnancy. 

Why is Multifetal Pregnancy Reduction Done?

More than one fetus can decrease the chances of a healthy pregnancy or may cause preterm birth. The higher the number of fetuses, the higher the risk a mother carries. Therefore, a fetal reduction procedure may help maintain a healthy pregnancy and minimize the risks and complications such as miscarriage, early delivery, dissabilities that may occur during the pregnancy.

What are the Risks Associated with Multifetal Pregnancy?

The risks that a mother faces during a pregnancy with more than one fetus are as follows:

Preeclampsia:

Preeclampsia is a condition that can happen during a multiple pregnancy. Symptoms of preeclampsia include high blood pressure, protein in their urine, swelling, headaches and blurred vision. According to a AHAJournal article, women having more than one fetus are 3 to 4 times more likely to experience preeclampsia, due to greater strain on the cardiovascular system, which is demonstrated by an increase in cardiac output and decrease in total vascular resistance.

Gestational diabetes:

Gestational diabetes is a form of diabetes that can develop in non-diabetic pregnant women, and it happens because the body is unable to produce sufficient insulin during pregnancy. Recent studies confirm that multifetal pregnancy has been associated with the risk of developing gestational diabetes.

Preterm birth:

Preterm birth is another risk associated with multifetal pregnancy. It is known that multiple pregnancy increases the probability of premature birth, as the increase in the number of fetuses causes the uterus to expand more.

Miscarriage and stillbirth:

The greater the number of embryos in your uterus, the higher your risk of miscarriage or stillbirth. To avoid this risk, MFPR may be advised to you by your doctor.

Increased maternal depression and anxiety:

A study from 2009 that was published in the journal of Pediatrics found that moms who are giving birth to multiple babies were 43% more likely to have postpartum depression than moms who only had one baby.

Risk factors for Multifetal Pregnancy on Fetuses

There are also several risk factors affecting the fetuses of multifetal pregnancy. Those are:

• Low birth weight: Babies of multiple births weigh less than singletons. This is because the already limited expansion capacity of the uterus undergoes further expansion than normal, thus restricting the further growth of the babies.

• Cerebral palsy: According to the CDC, children of multiple births have a higher risk of developing cerebral palsy, especially in the event that one of a baby's siblings passes away before or soon after the birth.

• Chronic lung disease: Chronic lung disease of prematurity is the indirect effect of multiple birth. The babies of multiple births are generally subjected to preterm birth. Preterm birth is associated with the incomplete development of several organs when baby is born. However, current techniques have increased the survival rate of these premature babies with medical conditions, such as chronic lung disease.

• Learning difficulties: Premature babies can also show increased risk for learning difficulties because they are born without completing their development.

How is MFPR Performed?

Fetal reduction procedures are ideally performed between 10th to 12th weeks of pregnancy. It is commonly done transabdominally because transvaginal or transcervical approaches have been found to be associated with higher risks of miscarriage.

Before performing MFPR, an examination should be performed to determine the position and chorionicity of the fetuses. The decision of which fetus or fetuses to abort is made by considering current screening results, the presence of early intrauterine growth restriction, or other evidence of a major fetal anomaly. If all prenatal diagnostic tests are normal, the most accessible fetuses are targeted for reduction. Ultrasound is used as a guide during the procedure. The doctor injects a drug containing potassium chloride into the selected fetus or fetuses with a needle inserted through the abdomen if transabdominal technique is applied. Thus, the embryo or fetus loses its vitality and is absorbed by the mother's body. The remaining fetus is monitored for a period of time to confirm the multifetal pregnancy reduction is successfully completed.

Fetal reduction should be distinguished from selective reduction, in which it is reduced because of a structural or genetic abnormality, regardless of the position of the fetus.

What Happens After MFPR?

You may experience slight bruising and pain at the needle insertion site. Spotting and bleeding is considered normal. Your doctor may prescribe medications for your pain. You should follow your doctor’s instructions for your recovery period. There are generally no restrictions for daily activities. However, resting for 3 days is recommended to minimize the possibility of infection.

If there is a high fever, severe vaginal bleeding or convulsions, you should immediately consult your doctor.

What are the Risks of MFPR?

The risks of the procedure are similar to the complications that may occur after the amniocentesis method. These include;

• leakage of amniotic fluid from the sac of a living fetus,

• placental abruption,

• infection (chorioamnionitis), and

• miscarriage.