Abstract
BACKGROUND: Sequential embryo transfer (ET) has been used to improve clinical outcomes in patients with recurrent implantation failure (RIF). This study aimed to evaluate whether sequential ET influence the live birth rate and perinatal outcomes of women with RIF. METHODS: A cohort study of RIF patients who underwent sequential ET (Seq-ET) during frozen-thawed embryo transfer (FET) cycles between January 2020 and June 2023 was performed. FET patients who underwent double cleavage-stage ET (D3-dET) and double blastocyst ET (D5/6-dET) during the same period composed the control group. The live birth rate and perinatal outcomes of the groups were analyzed and compared. RESULTS: The Seq-ET group had a significantly greater live birth rate (42.9%) than the D3-dET group (33.1%), and the live birth rate of the Seq-ET group was comparable to that of the D5/6-dET group (35.7%). Female BMI (aOR 0.96, 95%CI 0.92-1.00), stimulation for endometrial preparation (aOR 0.47, 95%CI 0.26-0.84), and endometrial thickness (aOR 1.08, 95%CI 1.00-1.16) were contributing factors to the live birth rate. No statistically significant differences were found in the rate of healthy birth or twins among the Seq-ET, D3-dET and D5/6-dET groups. There was no statistically significant difference in the rates of preterm delivery, birth weight or length, low birthweight, macrosomia, small for gestational age (SGA), gestational diabetes mellitus (GDM), gestational hypertensive disease (GHD), or the sex ratio among the three groups. The infants born in D5/6-dET group had less gestational weeks than in the Seq-ET and D3-dET groups (38.05 ± 1.88 vs. 38.43 ± 2.09 and 38.45 ± 1.80, P = 0. 013) and had a higher risk of large for gestational age (LGA) (aOR 2.15, 95%CI 1.00-4.62) compared to infants born in the D3-dET group. CONCLUSION: The live birth rate was significantly higher in the Seq-ET group compared with the D3-dET group, and slightly higher compared to the D5/6-dET group. Our results suggested sequential ET did not affect the perinatal outcomes.