Selective reduction

Selective reduction (or fetal reduction) is the practice of reducing the number of fetuses in a multifetal pregnancy (i.e. those involving more than one fetus). With selective reduction, a specific fetus or fetuses are "selected" for termination, usually after a congenital defect has been identified. Prenatal diagnostic testing may be used to determine which of the fetuses has a greater chance of chromosomal defect or genetic disease. Those fetuses are then targeted in selective reduction because of the probability of their health being inferior to that of the others.

The term multifetal reduction describes a procedure to reduce a higher-order multiple pregnancy (one with three or more fetuses) to a twin or singleton pregnancy, without targeting a specific fetus for reduction. It can also be used to reduce a twin pregnancy to a singleton one, but this is less common as the risks in twin pregnancies, while existent, are much lower than in higher-order multiple ones. The aim of multifetal reduction is to avoid the medical issues generally related to multiple births (including premature births, low birth weights and associated medical problems).

It is reasoned that if some of the fetuses will be terminated to preserve the well-being of the others and the mother, the ones that are terminated might as well be the ones that would, if born, face more health issues in addition to the ones inherent to all multiple births. This adds a new dimension of controversy; beyond the already controversial nature of abortion, critics charge that reduction is a form of eugenics.

The reduction procedure is generally carried out during the first trimester. The most common method is to inject a chemical solution or feticide into the fetus or fetuses selected for either genetic reasons or for ease of accessibility. Generally, the fetal material is reabsorbed into the woman's body. While the procedure generally reduces the over-all risk level for the remaining fetus or fetuses, reduction does have its own risks, including the possibility that one or more of the remaining fetuses will also die.

Selective or multifetal reduction can be a very difficult decision for those who choose to make it; in many cases it is a decision faced by couples who used fertility treatments that resulted in a multifetal pregnancy.