What is Selective Reduction?

When a woman is carrying multiple fetuses in a pregnancy, she is sometimes given the option of having selective reduction, a procedure to eliminate one or more fetuses from her womb. This is done so the woman may carry her remaining child or children to term with a better chance of having healthy babies without any medical problems. Selective reduction is also an option for a single fetus that has been tested and found to have debilitating birth defects.

Selective reduction is usually performed between the ninth and 12th weeks of a pregnancy and typically comes into play when there are four or more fetuses involved. The mother is given the option of reducing the number of fetuses to just one or two. In some cases, a set of triplets also may be reduced to just two fetuses. This is an option because multiple-fetus pregnancies can cause miscarriage or health problems for the other fetuses and the mother.

The procedure also may come into play when testing shows a fetus has a disease or deformity. The procedure can be performed if a doctor believes a fetus will die later in the pregnancy and is a health threat to the other fetuses. In these specific instances, the procedure is known as selective termination.

The procedure for selective reduction is to do a multifetal pregnancy reduction ultrasound. The woman is asked to lie down on an examining table and gel is placed on her abdomen. The doctor or technician runs a transducer probe across her abdomen, and the multiple fetuses are viewed on a monitor. Watching the monitor, the doctor will then place a needle through the woman's abdomen and inject a single or multiple fetuses in the heart with a solution of potassium chloride. This injection will stop the heart of the fetus.

At this stage, because selective reduction is done in the early part of the pregnancy, the fetus will be small. This will allow the fetus to be absorbed by the woman's body. The mother may have some vaginal bleeding or spotting following the procedure.

There are risks with selective reduction, as with any medical procedure. The remaining fetuses may end up being miscarried. The fetuses also may be born prematurely, causing health risks for a baby. A rare risk is that an infection can form in the abdomen or uterus of the woman having the procedure done.