Association between vitamin D levels, hormonal profile, and ovarian reserve in infertile women

Abstract Background and objective The potential influence of vitamin D on female reproductive function has recently gained considerable attention, yet its connection with hormonal dynamics and ovarian reserve remains uncertain. This study explored how circulating vitamin D concentrations relate to reproductive hormones and ovarian reserve indices among infertile women. Methods A retrospective cross-sectional study was conducted on medical records of 880 infertile women aged 18–45 years. Participants were grouped by serum vitamin D status as sufficient (≥ 30 ng/mL), insufficient (21–29 ng/mL), or deficient (≤ 20 ng/mL). Hormonal factors (FSH, LH, AMH, E2, TSH) and antral follicle count (AFC) were analyzed using Kruskal-Wallis and multinomial logistic regression. Results Nearly half of the women (47.4%) were vitamin D deficient. Those with deficiency exhibited significantly greater BMI values and lower LH concentrations compared with women having sufficient vitamin D ( p < 0.05). Regression modeling indicated that BMI positively predicted both insufficiency (OR = 1.045, p = 0.029) and deficiency (OR = 1.058, p = 0.001), whereas LH showed an inverse association with deficiency (OR = 0.964, p = 0.040). In adjusted analysis, higher AMH was associated with vitamin D insufficiency, whereas no significant association was observed for vitamin D deficiency. Conclusion Vitamin D deficiency was common among infertile women and was associated with higher BMI and lower LH levels. These findings support a possible link between vitamin D status and selected metabolic and hormonal parameters; however, longitudinal studies are needed before clinical implications can be established.