Birth weight discordance in spontaneous versus induced twins: impact on perinatal outcome.
PURPOSE: To compare the rate of birth weight discordance and perinatal outcome of twin pregnancies after assisted reproduction with that of spontaneous twins. METHOD: A total of 12,920 deliveries were analyzed retrospectively. Seventy-five twin pregnancies after ART were compared to the 94 spontaneous counterparts. Birth weight discordance was defined as a difference of 20% or more. RESULTS: Discordance rate was elevated (25.3% vs. 17.0%) among ART twins. SGA was increased and NICU admission was more frequent in discordant group. Unlike-sexed twins were more prevalent (73.7% vs. 37.5%) among discordants after ART. CONCLUSIONS: ART can increase discordance rate which can elevate perinatal risk.