Effect of spontaneous pregnancy reduction on obstetric outcome

To determine if obstetric outcome is compromised in pregnancies in which a spontaneous pregnancy reduction (SPR) occurred in the first trimester.

Case-control study.

First-trimester SPR was diagnosed in 29 (27.8%) of 104 twin pregnancies, 14 (28.6%) of 49 triplet pregnancies and 10 (28.6%) of 35 quadruplet pregnancies. Of these 53 patients, 15 were excluded from the analysis. In the remaining 38 women with SPR, vaginal bleeding occurred in 2 (5.3%) as compared to 7 (8.3%) of the controls. Pregnancy-induced hypertension occurred in 4 (10.5%) of SPR pregnancies as compared to 9 (10.7%) of control pregnancies. When compared to respective controls, there were no significant differences in the birth weights or gestational age at delivery of pregnancies spontaneously reduced to singletons (SPR, 38.5 weeks; controls, 38.2 weeks), twins (SPR, 36.2 weeks; controls, 34.4 weeks) or triplets (SPR, 31.0 weeks; controls, 32.0 weeks).

SPR can be recognized in >25% of multiple pregnancies diagnosed in the early first trimester. Our data suggests that SPR is not associated with decreased gestational age at delivery, reduced birth weight or increased incidence of pregnancy-induced hypertension.