研究開発・学会発表

【Background】 The aim of this study is to investigate the optimal way of progesterone supplementation in women who undergo frozen-thawed embryo transfer (FET).

【Methods】 This study included 1493 FET cycles from 2011 to 2014. Analysis was limited to FET cycles utilizing hormone replacement cycles with estradiol and progesterone supplementation, and was also limited to blastocysts graded 3BB or higher. Progesterone was administered using vaginal United States Pharmacopeia (USP) progesterone. Among 1493 cycles, 1202 were administered with 1200mg/day of USP progesterone (USP 1200 group) and 291 were administered with 900mg/day (USP 900 group). The baseline characteristics of several factors including serum progesterone levels were the same in both groups. Serum progesterone levels and estradiol levels were measured on luteal day 0, 8 and 15. Additional progestin medications such as hydroxyprogesterone caproate were used when serum progesterone levels were below 9 ng/ml on luteal day 8.

【Results】 The mean serum progesterone level on luteal day 8 in USP 1200 group and USP 900 group were 12.5 ng/ml and 13.2 ng/ml respectively and was significantly higher in USP 900 group (p<0.001). The clinical pregnancy rate and live birth rate were not significantly different between the two groups. Furthermore, there was no statistical difference in the clinical outcome in cases that utilized any additional type of progestin medications.

【Conclusions】 USP 900mg/day is enough dosage of progesterone supplementation during FET cycles. In patients whose serum progesterone levels were relatively low after USP administration, the choice of additional progestin medications did not affect the clinical outcome.