Multifetal pregnancy reduction is a procedure to reduce the number of fetuses in a pregnancy—usually from three, four, or five fetuses to two. This may help the two fetuses survive and help you have a healthy pregnancy.

This procedure is most often done early in a pregnancy, between the 9th and 12th weeks. It's often done after genetic testing to find out if the fetuses have any problems.

It's usually done through the belly. Using ultrasound as a guide, the doctor puts a needle into the uterus to the selected fetus or the umbilical cord. The doctor injects the fetus or the cord with a medicine that stops the heart.

Sometimes vaginal bleeding happens afterward. This is normal.

The dead embryo or fetus is absorbed by the mother's body. This is similar to what happens with vanishing twin syndrome.

Reduced risk for mother. The procedure reduces the mother's risk of problems. These risks include gestational diabetes, pre-eclampsia, and anemia. These risks increase with each added fetus.

Reduced risk for infants. The procedure may improve your chances of carrying your pregnancy longer and your chances of delivering one or more healthy babies.

Carrying triplets or more increases the risk of miscarriage, stillbirth, premature birth, and disability.

Reduced stress related to infant care. Caring for three or more babies can be stressful, especially if any of them has health problems.

Reduced cost of caring for multiples. The hospital care for three or more infants can be expensive. Your provincial health plan or private health insurance may cover some of these costs. Because multiple babies have an increased chance of premature birth and illnesses, they are cared for in a neonatal intensive care unit (NICU). Caring for the babies at home also could be costly. After they come home, premature babies often need medicines, medical equipment and supplies, and extra doctor visits.

The risks of reducing the number of fetuses include:

• Miscarriage of the other fetuses. About 4 out of 100 triplet-to-twin procedures and about 7 out of 100 quadruplet-to-twin procedures lead to miscarriage. This means that 96 out of 100 triplet-to-twin procedures and 93 out of 100 quadruplet-to-twin procedures don't cause a miscarriage.^{footnote 1} The miscarriage rate is highest when reducing from 6 or more fetuses. The miscarriage rate is lower if there are fewer fetuses at the start of the procedure.^{footnote 1}
• Emotional risks for you, especially if the pregnancy miscarries. Some parents who go on to have a healthy pregnancy view the reduction as sad but medically needed. Others who have had a reduction followed by a healthy pregnancy say they felt grief, guilt, and depression about their decision. But for many women these feelings usually are reduced with time.^{footnote 2}
• Infection of the belly or uterus. This is rare.

Some couples choose to implant fewer embryos to reduce the chance of a pregnancy of triplets or more, rather than consider having this procedure.