Serum total testosterone (TT) concentration is critical for male reproductive function, but its role in predicting in vitro fertilization–embryo transfer (IVF-ET) outcomes in patients with azoospermia remains unclear. In this retrospective study, the association between TT concentrations and clinical pregnancy outcomes was investigated in 2101 patients with azoospermia (1846 with obstructive azoospermia [OA] and 255 with nonobstructive azoospermia [NOA]) at The First Affiliated Hospital of Zhengzhou University (Zhengzhou, China), from January 2010 to January 2023. General characteristics of the patients in the pregnancy and nonpregnancy groups were compared. Logistic regression analysis was used to identify factors that affect pregnancy outcomes. A receiver operating characteristic curve (ROC) was plotted to determine the cut-off value of the TT concentration. Embryonic and clinical outcomes were compared using the TT cut-off value. The results revealed a significant negative correlation between the TT concentration and body mass index (BMI) in both cohorts. In patients with OA, female age (odds ratio [OR] = 0.96, 95% confidence interval [CI]: 0.92–0.99; P = 0.024) and the male TT concentration (OR = 1.14, 95% CI: 1.04–1.24; P = 0.005) were independent pregnancy predictors. We identified the TT concentration of 268 ng dl−1 as the favorable cut-off value. OA patients with TT levels of <268 ng dl−1 exhibited poorer sperm quality, reduced blastocyst formation, and diminished reproductive outcomes (all P < 0.05). We conclude that the TT concentration is correlated with BMI in patients with azoospermia and serves as an independent predictor of clinical pregnancy outcomes in patients with OA, but not in those with NOA. This provides a valuable clinical reference for subtype-specific management. However, its modest predictive performance limits its standalone clinical use.

Keywords: azoospermia; BMI; clinical pregnancy outcomes; IVF-ET; total testosterone concentration