Factors affecting occurrence of twin pregnancy after double embryo transfer on day 3.

Aim The aim of this study was to identify the risk factors of twin gestation in fresh double day-3 embryo transfer cycles. Material and Methods Out of a total of 386 cycles of fresh double embryo transfers on day 3 between 2006 and 2013 at a single center, 72 women with single intrauterine gestational sac (GS) (single-GS group) and 32 women with double GS (double-GS group) were identified. The patients' clinical characteristics and laboratory results were extracted from electronic medical records and were compared. Results The double-GS group had a significantly younger age ( P = 0.012), and higher bodyweight ( P = 0.033) compared with the single-GS group. The total number of blastomeres ( P = 0.013) and cumulative embryo score ( P = 0.012) were higher in the double-GS group. By receiver-operator curve analysis, maternal age ≤ 35 years, maternal bodyweight > 60 kg, total number of blastomeres > 14, and cumulative embryo score > 49 were the cut-off values to predict twin pregnancy. Among eight women with all four risk factors, the twin pregnancy rate was 87.5%. There was no twin pregnancy among seven women with no risk factors. Conclusion Younger age, higher bodyweight, and better embryo quality are all associated with a higher incidence of twin pregnancy after double embryo transfer on day 3. Single embryo transfer might be advisable for couples with risk factors for twin pregnancy. [ABSTRACT FROM AUTHOR]