Effects of Clomiphene Citrate Ovulation Induction on Frozen Embryo Transfer

Clomiphene citrate has been widely used for treatment of infertility for decades. Although its anti-estrogenic effects leads to low pregnancy rate, clomiphene citrate is still a first-line treatment for ovulation induction because of its simple usage, low prices, no injection and low risk of ovarian hyperstimulation syndrome. Clomiphene citrate shows high affinity with estrogen receptor, which inhibits endometrial proliferation, inevitably leads to a decline in endometrial receptivity, thus affecting the success rate of IVF. In that case, use clomiphene citrate for ovulation induction is lost more than gained based on fresh embryo transfer. But recently, some researchers have proposed to extend the time from ovulation induction to embryo transfer, and the increased level of estradiol can replace clomiphene citrate to combine with the receptor, so that the uterine environment is more conducive to pregnancy. Therefore, use clomiphene citrate based on vitrification of embryo maybe a good way for treatment of infertility. At present, using frozen embryo transplantation after ovulation induction by clomiphene citrate is a common treatment, but few research has mentioned the best time for embryo implantation. The investigators research is to find the most appropriate time for frozen embryo implantation after using clomiphene citrate for ovulation induction.