Effect of serum progesterone levels on hCG trigger day on pregnancy outcomes in GnRH antagonist cycles

OBJECTIVE: The present study analyzed the effect of hCG trigger day progesterone (P) levels on the live birth rate (LBR) in the gonadotropin-releasing hormone (GnRH) antagonist protocol. MATERIALS AND METHODS: This study was a single-center retrospective study. In vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles performed from January 2017 to December 2020 were included in the analysis. This study included people with a normal ovarian response to fresh embryo transfer of GnRH antagonist protocols. All cycles were divided into 2 groups by P level on the day of human chorionic gonadotropin (hCG) trigger, P<1.0 ng/ml and P≥1.0 ng/ml. The primary outcome measure was LBR. RESULT: A total of 867 cycles with P<1.0 ng/ml and 362 cycles with P≥1.0 ng/ml were included in the analysis. The clinical pregnancy rate (CPR) was higher in the P<1.0 ng/ml group than the P≥1.0 ng/ml group (44.9% vs. 37.6%, P=0.02). The early spontaneous abortion rate was comparable between the groups (14.4% vs. 14.7%, P=0.93). For live birth, the rate for the P<1.0 ng/ml group was 35.3%, which was significantly higher than the 29.0% in the P≥1.0 ng/ml group (P=0.03). After binary logistic regression analysis, the P level on the hCG trigger day (adjusted odds ratio=0.74, 95% CI=0.55-0.99, P=0.04) was an independent risk factor for LBR. For the P level on the hCG trigger day, the LBR was lower in the P≥1.0 ng/ml group compared to the P<1.0 ng/ml group. CONCLUSION: For normal ovarian response patients using the GnRH antagonist protocol, serum P≥1.0 ng/ml on the hCG trigger day resulted in a lower LBR than the P<1.0 ng/ml group. When P≥1.0 ng/ml, whole embryo freezing may be considered.