Embryo reduction in multifetal pregnancies after infertility therapy: obstetrical risks and perinatal benefits are related to operative strategy. To assess the benefits that can be expected from embryo reduction of multiple pregnancies after infertility therapy, we report 58 consecutive cases of selective termination using either a transcervical or a transabdominal approach. The initial number of embryos was five or more in 13 patients, four in 29 patients, and three in 15 patients. The miscarriage rate after transabdominal procedures (23%) was one half of that after transcervical aspiration. Forty pregnancies resulted in the live birth of one child or more. The rate of prematurity was strongly related to the number of embryos left. Mean gestational age at birth was 35.5 weeks but reached 37.7 weeks when only one embryo was left. A reduction in premature birth after selective termination appeared clear for pregnancies with four or more embryos but was less significant for triplets. 