Association Between Progesterone Level on Trigger Day to Basal Progesterone Ratio and in vitro Fertilization-Embryo Transfer Outcomes in Antagonist Protocols.

OBJECTIVE

To investigate the relationship between the progesterone level on trigger day (Ptrigger) to basal progesterone (bP) ratio and the outcomes of in vitro fertilization-embryo transfer (IVF-ET).

METHODS

A retrospective analysis was conducted on women who received an antagonist protocol, with a Ptrigger less than 1.5 ng/mL and who underwent fresh embryo transfer. Based on the Ptrigger/bP ratio, participants were categorized into four groups: group A (Ptrigger/bP < 1, n = 284), group B (Ptrigger/bP ≥ 1 and < 2, n = 363), group C (Ptrigger/bP ≥ 2 and < 3, n = 165), and group D (Ptrigger/bP ≥ 3, n = 118). Recombinant follicle-stimulating hormone was used to stimulate ovulation. Receiver operating characteristic curve analysis was used to analyze the accuracy of the Ptrigger/bP ratio in predicting clinical pregnancy following fresh embryo transfer.

RESULTS

A decreasing trend in bP levels was observed across groups (A > B > C > D), while Ptrigger levels showed an increasing trend (A < B < C < D). Groups A and B included significantly younger women and required lower doses of gonadotropin (Gn) compared to Groups C and D. The embryo implantation and clinical pregnancy rates in Group A were 34.93% and 49.30%, respectively, significantly higher than those in Group D (23.19% and 33.90%, respectively). After propensity score matching for age, the differences in implantation and clinical pregnancy rates were not statistically significant between Group A and D. The Ptrigger/bP ratio had limited accuracy in predicting clinical pregnancy, with an area under the curve of 0.538 (95% CI [confidence interval]: 0.501-0.575, P = 0.044).

CONCLUSION

A Ptrigger/bP ratio of less than 1 was associated with relatively favorable pregnancy outcomes in women undergoing IVF-ET with an antagonist protocol for ovulation induction.