A comparative study on the impact of fresh variables on the success of frozen-thawed embryo transfer cycles using 2PN sibling embryos in women with/without polycystic ovary syndrome

Abstract

Aims: The aim of the present study was to identify the fresh variables that influence the frozen-thawed embryo transfer (FET) outcome using sibling two pronuclei (2PN) embryos in women with polycystic ovary syndrome (PCOS) and non-PCOS women. Material & methods: Fifty-five FET cycles were performed using sibling embryos randomly cryopreserved at 2PN states and basal/cycle characteristics of fresh variables were compared between PCOS and non-PCOS groups according to the success in FET pregnancy: group A (pregnant PCOS); group B (not pregnant PCOS); group C (pregnant non-PCOS); group D (not pregnant non-PCOS). Results: In PCOS patients, higher progesterone level on human chorionic gonadotropin (hCG) day was observed in group A than in group B (0.9 ± 0.0 vs. 0.5 ± 0.3, p = 0.004). In non-PCOS patients who achieved a pregnancy in the fresh cycle, a subsequent FET cycle using sibling 2PN embryos conferred a thirteen times increased chance of achieving pregnancy (OR 13.0; 95% CI, 2.3–74.1). Embryo quality and endometrial maturation were comparable between A and B or C and D. Conclusions: The success of the fresh embryo transfer (ET)was the most important predictor of pregnancy in FET cycles in the non-PCOS group. The relationship between serum progesterone on hCG day in the fresh cycle and the outcome of subsequent FET would benefit further evaluation in PCOS group.