Abstract: Objective：To explore the effect of days of the elevated serum progesterone before hCG administration on the outcomes of IVF/ICSI-ET treatment. Methods：2 905 cases of IVF/ICSI -ET treatment, from June 2012 to June 2013, were divided into two groups according to whether finding the follicle（ｓ） of diameter≥20 mm （Group A 2 725 cases, and Group B 180 caｓｅｓ） on the hCG day. Two groups were respectively divided into 3 subgroups according to days of the elevated level of progesterone （＞１ ｎg/mL）． Group A1 （１ ７８８ ｃａｓｅｓ） and B１ （８３ ｃａｓｅｓ） ｈａd 0 day of the elevated level of progesterone. Group A２ （７１７ ｃａｓｅｓ） and B2 （６７ ｃａｓｅｓ） ｈａd 1-2 days of the elevated level of progesterone. Groups A３ （２２０ ｃａｓｅｓ） ａｎｄ Ｂ３ （３０ ｃａｓｅｓ） ｈａd ≥3 days of the elevated level of progesterone. The clinical pregnancy rates of groups were meticulously compared. Results：There was significant difference in the clinical pregnancy rates among the Group A1 (55.42%), A2 (44.21%) and A３ （４１．８１％, Ｐ＜０．０１）． Ｉｎterestingly, there was no significant difference in those rates among the Group B1 （４８．１９％）, B2 （４７．７６％） ａnd B3 （４６．６６％, Ｐ＞０．０5）． Conclusions：The clinical pregnancy rate could decrease following days of the elevated level of serum progesterone （＞１ ng/mL） in those IVF/ICSI-ET patients with the folliclｅ（ｓ） of diameter ≥20 mm on the hCG day.

Key words: Fertilization in vitro, Sperm injections, intracytoplasmic, Embryo transfer, Progesterone, Pregnancy