By 2017, many centers have adopted embryo cryopreservation as their primary IVF therapy, and perform few or no fresh embryo transfers. The two main reasons for this have been better endometrial receptivity when embryos are transferred in cycles without exposure to ovarian stimulation and also the ability to store the embryos while awaiting the results of pre-implantation genetic testing.
Treatment with Clomid tablets plus IUI improves fertility rates. For unexplained infertility, studies have shown that for women under 35, monthly success rates for Clomid plus insemination are about 10% per cycle. This pregnancy rate holds up for about 3 tries and the success rate is considerably lower after that. More about success rates with IUIs is on the insemination page and on the Clomid for unexplained infertility page. The insemination component boosts fertility more than the Clomid does - but success rates are higher when both are used together.
Repeated failed rounds of IVF can help identify causes of infertility. For example, if sperm and egg quality are normal, then the conception issue may be rooted at the embryonic or implantation level. In other words, if IVF fails to result in pregnancy despite successful fertilization, embryonic development or implantation may be to blame. Still this is a very expensive way to start getting answers.