Temporal changes in serum anti-Müllerian hormone concentrations before, during, and after the COVID-19 pandemic: A retrospective study of 1799 women.

To evaluate temporal differences in anti-Müllerian hormone (AMH) levels in women attending a reproductive medicine unit before, during, and after the COVID-19 pandemic. A retrospective observational study included 1,799 women who underwent fertility evaluation between 2019 and 2022. Participants were classified into pre-pandemic (2019), pandemic (2020-2021), and post-pandemic (2022) periods. Serum AMH levels, age, and body mass index (BMI) were recorded at the initial visit. Analysis of covariance (ANCOVA) was performed using log-transformed AMH as the dependent variable, study period as the fixed factor, and age and BMI as covariates. After adjustment for age and BMI, study period was significantly associated with AMH levels (F(2,1794) = 4.406, p = 0.012), although the effect size was very small (partial η2 = 0.005). Adjusted AMH levels were slightly lower in the pre-pandemic than in the post-pandemic period, whereas no significant differences were observed between the pandemic and post-pandemic periods. Age was inversely associated with AMH levels, whereas BMI showed a weak positive association. Although statistically significant differences in AMH levels were observed across study periods, the effect size was negligible, indicating limited clinical relevance. Overall, AMH concentrations remained largely stable throughout the study period. Because individual data on SARS-CoV-2 infection and vaccination were unavailable, these findings should be interpreted as comparisons between study periods rather than as evidence of the direct biological effects of COVID-19 infection on ovarian reserve. Prospective longitudinal studies are warranted.