Multi-fetal pregnancy reduction (MFPR) to twins or singleton - medical justification and ethical slippery slope.

Multi-fetal pregnancy reduction (MFPR) is an ethically acceptable procedure aimed to increase survival and well-being of the remaining fetuses from high-order multiple gestations. In most cases we offer the procedure to triplets or quadruplets and opt to preserve twins; lately, the option to maintain a single fetus was suggested. We examined the outcomes of 140 pregnancies that underwent MFPR in our center and were followed to delivery - 105 were reduced to twins and 35 to singletons. The rate of procedure-related pregnancy loss was identical (2.9%). Leaving only one fetus was associated with a higher gestational age at delivery (35.4±2.4 weeks vs. 37.7±2.1 weeks, P<0.0001), with heavier neonates (2222 g vs. 3017 g, P<0.0001) and with a reduction in the cesarean section (CS) rate (76% in twins vs. 51.4% in singletons, P=0.02). Six pregnancies reduced to twins (5.8%) ended before 32 weeks as compared to one pregnancy reduced to a singleton. We conclude that reduction of triplets to singletons is medically and ethically acceptable, after thorough counseling of patients. However, considering the pregnancy loss risk of MFPR and the relatively good outcome of twin gestations, reduction of twins to singletons is ethically acceptable only in extraordinary maternal or fetal conditions.