Objective: To compare the obstetric outcomes of twin pregnancies obtained as a result of multifetal pregnancy reduction to those in which pregnancy reduction had not been used.
Design: Retrospective analysis.
Setting: University-based tertiary care infertility clinic.
Patients: Seventy-four twin pregnancies continuing beyond 10 weeks. Of these, 32 gestations had undergone reduction to twins at 10 weeks.
Main outcome measures: Gestational age at delivery, birth weights, pregnancy complications.
Results: All pregnancies advanced beyond 20 weeks gestation. The mean gestational age at delivery of the reduction group was 33.8 versus 35.7 weeks in the nonreduced group; only 25% of reduced pregnancies reached 37 weeks compared with 57.9% of nonreduced twins. The mean fetal birth weights of the two groups differed significantly (reduced: 2,038 g, nonreduced: 2512 g). The gestational age at delivery in patients reduced from triplets was significantly greater than in pregnancies reduced from quadruplets or higher. Multiple regression analysis revealed that for a given gestational age at delivery, a history of pregnancy reduction was associated with decreased birth weight.
Conclusion: These data suggest that multifetal pregnancy reduction does not reverse completely the decreased gestational age and impaired fetal growth associated with high-order multiple pregnancy. Furthermore, fetal growth of reduced pregnancies seems to be impaired independent of the gestational age at which delivery occurs.