Improvement in outcomes of multifetal pregnancy reduction with increased experience

OBJECTIVE: This study was undertaken to evaluate a decade of data on multif etal pregnancy reductions at centers with extensive experiences. STUDY DESIGN: A total of 3513 completed cases from 11 centers in 5 countrie s were analyzed according to year (before 1990, 1991-1994, and 1995-1998), starting and finishing numbers of embryos or fetuses, and outcomes. RESULTS: With increasing experience there has been a considerable improveme nt in outcomes, with decreases in rates of both pregnancy loss and prematur ity. Overall loss rates in the last few years were correlated strongly with starting and finishing numbers (starting number greater than or equal to6, 15.4%; starting number 5, 11.4%; starting number 4, 7.3%; starting number 3, 4.5%; starting number 2, 6.2%: finishing number 3, 18.4%; finishing numb er 2, 6.0%; finishing number 1, 6.7%). Birth weight discordance between sur viving twins was increased with greater starting number. The proportion of cases with starting number greater than or equal to5 diminished from 23.4% to 15.9% to 12.2%. The proportion of patients >40 years old increased in th e last 6 years to 9.3%. Gestational age at delivery did not vary with incre asing maternal age but was inversely correlated with starting number. CONCLUSION: Multifetal pregnancy reduction outcomes at our centers for both losses and early prematurity have improved considerably with experience. R eductions from triplets to twins and now from quadruplets to twins carry ou tcomes as good as those of unreduced twin gestations. Patient demographic c haracteristics continues to change as more older women use assisted reprodu ctive technologies. In terms of losses, prematurity, and growth, higher sta rting numbers carry worse outcomes.