The Association between Baseline Serum SHBG and the Number of Retrieved Oocytes in Chinese Infertile Patients Undergoing IVF Treatment of PPOS Protocol: A Restrospective Cohort Study

This study aimed to investigate the association between the baseline circulating sex hormone binding globulin (SHBG) concentration and the number of oocytes retrieved. This retrospective cohort study included 1477 patients who underwent PPOS treatment from January 2018 to December 2019 at the reproductive centre of Shiyan Renmin Hospital, Hubei, China. We investigated the potential relationships of SHBG and the number of oocytes retrieved using piecewise linear regression and multiple logistic regression, respectively. Our results show that baseline SHBG was negatively associated with the number of oocytes retrieved (β= -0.07, 95% CI (-0.13, -0.02)) by fully adjusted linear regression. After adjusting for potential confounders, a nonlinear relationship was found between baseline SHBG and the number of oocytes retrieved (P=0.01). The number of oocytes decreased with SHBG levels above 55.4 nmol/L. A high level of SHBG (SHBG ≥ 55.4) was associated with a lower yield of oocytes (adjusted β=-0.11, (per 10 nmol/L for SHBG), 95% CI (-0.17, -0.05), p=0.0003). The relationship between baseline SHBG and the number of oocytes retrieved is nonlinear. A higher baseline SHBG level is associated with a lower yield of oocytes in PPOS cycles.