The current status of multifetal pregnancy reduction.

The number of women conceiving three or more fetuses has increased dramatically as a result of successful infertility therapy with ovulation-inducing agents and assisted reproductive technology. Higher-order multiple gestations have an increased risk of premature delivery and its attendant sequelae of increased neonatal mortality or irreversible morbidity. Multifetal pregnancy reduction is a procedure designed to decrease the increased propensity to deliver very prematurely in these patients by reducing the number of live fetuses they are carrying. The procedure has proved to be both safe and effective, and pregnancies reduced to twins proceed as if that were the number of fetuses originally conceived. Nevertheless, this invasive procedure does have the potential to result in loss of the entire pregnancy and causes considerable emotional distress for some couples who view it as their "least bad" alternative. The medical benefits of performing multifetal pregnancy reduction in women with four or more fetuses seem fairly well established, but this is less true for triplets. Serious attention should be paid to reducing the number of higher-order multiple pregnancies resulting from infertility therapy. In the meantime, when three or more fetuses have been conceived, multifetal pregnancy reduction offers a reasonable option to patients whose only choices in the past were either to accept the risk of delivering extremely prematurely or to terminate the entire pregnancy.