Selective reduction of multifetal pregnancies to twins improves outcome over nonreduced triplet gestations.

Objective: Our purpose was to evaluate effects of multifetal pregnancy reduction on pregnancy complications and birth weights of remaining twin fetuses compared with expectantly managed triplets and nonreduced twins.
Study Design: Medical records of 54 triplet pregnancies, 59 twin pregnancies resulting from multifetal pregnancy reduction, and 88 sets of twins conceived with assisted reproductive techniques and delivered at New York Hospital after 24 weeks were retrospectively reviewed. Birth weights were corrected for gestational age at delivery by use of a formula derived from composite standardized growth curves. Statistical analysis was performed with chi(2) analysis and Student t test.
Results: Twins remaining after reduction and nonreduced twins were less likely to have preeclampsia than were triplets (14% and 23% vs 30%) and to be delivered before 36 weeks (39% and 27% vs 72%). They had birth weights that were > 100 gm larger than those of triplets even when corrected for gestational age. Reduced twins were similar to nonreduced twins in all parameters studied.
Conclusions: Multifetal pregnancy reduction results in pregnancy complications, gestational age, and birth weights closer to those of nonreduced twins than to expectantly managed triplets.