Association between progesterone level on human chronic gonadotropin (hcg) trigger day and clincal outcomes of cleavage-stage embryos or blastocysts transfer in assisted reproduction technology (art) cycles.

Several studies have reported that increased progesterone levels, usually defined as greater than 1.5 ng/mL, occur on the human chronic gonadotropin (hCG) day in approximately 6-30% of COH cycles. The increased serum progesterone level on the day of hCG administration is associated with significantly lower ongoing pregnancy rates in in vitro fertilization and embryo transfer (IVF-ET) cycles. However, the effect of increased serum progesterone levels on the day of hCG administration in COH cycles on clinical outcomes for different embryos transfer remains controversial. Therefore, we conducted a retrospective study of long-acting gonadotropin-releasing hormone agonist (GnRHa) ART cycles. A non-interventional, retrospective, observational, single center cohort study was employed. A total of 1951 patients who received long-acting GnRHa for pituitary down-regulation in the reproductive medicine center of Nanjing Drum Tower Hospital from January 2018 to December 2020 were involved to further evaluate the relationship between serum progesterone level on the day of hCG trigger and clinical pregnancy outcomes. When the serum progesterone level on the hCG day was higher than 1.5 ng/mL, the clinical pregnancy rate did not decrease significantly. There was no correlation between clinical pregnancy rate of cleavage-stage embryos transfer and serum progesterone level on the hCG day. With the increase of serum progesterone level on the hCG day, the clinical pregnancy rate of patients receiving blastocysts transfer reduced. The pregnancy rate of patients with lower progesterone level (≤ 1.05 ng/mL) was significantly higher than that of patients with higher progesterone level. Multiple regression analysis showed that progesterone level on the day of hCG administration was closely related to the clinical pregnancy rate of blastocysts transfer. The increase of serum progesterone level on the day of hCG administration did not affect the clinical pregnancy rate of cleavage-stage embryos transfer. When the serum progesterone level on the hCG day was higher than 1.05 ng/mL, the clinical pregnancy rate of blastocysts transfer was significantly reduced. At this time, double cleavage-stage embryos transfer might become a better choice.