Research and Clinical Center of Gynecology and Fertility, Shahid Akbarabadi Hospital, Iran University of Medical Sciences, Tehran, Iran


Background: The present Randomized controlled trial (RCT) was conducted to evaluate reproductive outcomes of frozen embryo transfer (FET) during hormonally intervened cycle and also during physiological condition.

Methods: The present RCT was conducted on 200 couples (240 cycle) with male-originated infertility aged 19 to 39 years at the Infertility Clinic of Shahid Akbar Abadi hospital, Tehran. The Participants were randomly allocated into two group; the natural cycle (n=115 cycle) and hormonal cycle (n=125 cycle). The hormonal group was received 4-6 mg of oral estradiol on the third day of their cycles; while controls received placebo. Transvaginal ultrasound was used for evaluation of endometrial thick- ness and when the thickness was reached to8 mm, embryo transfer was planned. Chemical and clinical pregnancy were consid- ered to be the primary and secondary outcomes, respectively.

Results: A total of 28 cycles were cancelled in both groups; 15 cycles (8.3 percent) in the natural group and 13 cycles (7.6 percent) in the hormonal group. Inter-groups statistical analysis showed that serum levels of FSH, LH and estradiol were not sta- tistically different between the study groups (P>0.05). On the other hand, chemical clinical pregnancy rate (hormone receiving group: 32.7% and control group: 33.3%) and clinical pregnancy rate (hormone receiving group: 34.5% and control group: 26.4%) statistically were not different between the groups (P> 0.05).

Conclusion: The study results showed there is not any statistical significant difference between the study groups from point of view of chemical and clinical pregnancy rate. There is still a controversy whether one is superior over the other, so further studies are needed.


Endometrium thickness, Pregnancy outcome, Hormonal cycle, natural cycle.