ABSTRACT
Objective: To evaluate the effect of early progesterone elevation on clinical pregnancy and abortion rates in freeze-all cycles. Material and Methods: Assessments were carried out on patients who underwent frozen embryo transfer (FET) between 2015 and 2018 after tertiary referral at the Ondokuz Mayıs University In-Vitro Fertilization (IVF) Center, Samsun, Turkey. Serum progesterone levels were measured at the beginning (p1) and on the 11th day (p2) of the HRT cycle, and two subgroups were identified as <1.5 ng/L and ≥ng/L. Results: FET was indicated for 204 women with symptoms of unexplained infertility (n=130), male factor (n=54), or poor ovarian reserve (n=20). No significant correlation was found between clinical pregnancy rates and progesterone levels on the 2nd to 3rd day (p=0.389) nor on the 11th day of the HRT cycle (p=0.407). Similar results were also obtained for the correlation between the abortion rates and progesterone levels on the second, third, or 11th days of the cycle (p=1.000, not significant). Conclusion: Although progesterone elevation is believed to cause early maturation of the endometrium, the present findings indicate clinically nonsignificant effects of progesterone levels on pregnancy and abortion rates in frozen cycles.