Reproductive Outcomes of Single Embryo Transfer in Women with Previous Cesarean Section.

The aim of this study is to evaluate the reproductive outcomes of patients with previous cesarean section (CS) undergoing single-embryo transfer (SET). A total of 5479 patients previously underwent CS or vaginal delivery (VD) were included. The patients with previous CS included single/double cleavage (SCT/DCT), single/double blastocyst stage embryo transfer (SBT/DBT). The comparison of reproductive outcomes between CS and VD, SET, and double-embryo transfer of CS was conducted. The main outcome measures included clinical pregnancy rate (CPR), multiple pregnancy rate (MPR), live birth rate (LBR), and cumulative live birth rate (CLBR). There were no differences in CPR and LBR between patients previously underwent CS and VD, and the preterm birth rate of multiple births in patients underwent CS were significantly higher than underwent VD. As for patients underwent CS, the CPR, MPR, and LBR were lower in patients treated with SCT than DCT in IVF/ICSI cycles. The CPR and LBR of patients treated with SCT were not statistically different compared with DCT and SBT when patients' age were younger than 35 years in FET cycles, and the MPR of patients treated with SCT was lower. The CPR and LBR of patients treated with SCT were lower than DCT/SBT when patients' age were 35 years or older in FET cycles. The CPR, LBR, and CLBR of patients treated with SBT were not lower than DCT in IVF/ICSI-ET, FET, and complete cycles, but the MPR was lower. Reducing the number of embryos transferred should be considered seriously for CS. SCT under the 35 years of FET cycles is feasible. SBT is an effective strategy to reduce MPR of IVF/ICSI, FET, and complete cycles regardless of overall or age stratification.