The objective of this work was to evaluate the outcome of multifetal pregnancy reduction and to provide an analysis of the ethical dilemmas associated with its application. The study design was based on data on over 1400 completed pregnancies that underwent multifetal pregnancy reduction as reported in the world literature during 1993-1996. The results were: A total of 1453 completed cases of multifetal pregnancy reduction are presented. The total survival rate was estimated to be 87.7%, resulting in a total pregnancy loss rate of 12.3%. The lowest survival rate is found to be in higher-order pregnancies of five or more fetuses (75.2%), whereas pregnancy loss rate seems to be similar for quadruplets, triplets and twins that underwent reduction (11.3%, 8.3% and 13.6%, respectively). A 33.3% of the total pregnancy loss rate occurred within four weeks from the procedure, whereas 66.7% occurred after the four weeks but at 24 weeks of gestation or earlier. The mean gestational age at delivery was estimated to be 33 weeks for pregnancies reduced to triplets, 35.8 weeks for those reduced to twins and 36.9 weeks for singletons, with 5% delivering at less than 28 weeks and 9.6% at 29-32 weeks. We conclude that multifetal pregnancy reduction has been established as an efficient and safe way to improve outcome of multifetal gestations, especially those with four or more fetuses and likely of triplets. As the experience from the procedure increases, it seems that reduction of triplets to twins can be offered to patients with satisfactory results. The reduction to singletons has not yet been established and is being performed only when medical indications exist. Prenatal genetic diagnosis should become an integral part of counselling on multiple pregnancy. Physicians should take whenever possible measures designed to prevent high multiple birth pregnancies. We also note that although multifetal pregnancy reduction improves significantly the outcome of multiple pregnancies, several ethical dilemmas arising from its application are still under dispute.