Key predictors of fertility: Exploring the role of Vitamin-D.

Background & objectives: The relationship of Vitamin-D (VD) with Luteinizing Hormone (LH), Follicle stimulating Hormone (FSH) and Anti Mullerian Hormone (AMH) is recognized. This study was conducted to determine whether VD is a predictor of fertility and investigate its relationship with female reproductive hormones and markers of ovarian reserve in female population of Karachi.

Methods: A cross-sectional study was performed from July 2020 to June 2022 at the Aga Khan University Hospital (AKUH) with recruitment of 135 fertile and infertile subjects. VD, AMH, FSH and LH levels were estimated by 'Enzyme Linked Immunosorbent assay (ELISA)'. By applying binary logistic regression, variables with p-value < 0.25 in univariate analysis were used for multivariate regression model and adjusted odds ratios were computed. In multivariate analysis, significance was p-value ≤ 0.05.

Results: VD deficiency was observed in all infertile female subjects. In univariate regression analysis, FSH, LH, LH/FSH ratio and VD levels turned out to be significant. The Multivariate analysis represented that for every one ng/mL increase in VD level, the odds of fertility were expected to be 50.154 times higher with p-value < 0.001. The positive correlation of VD with FSH was significant.

Conclusion: VD deficiency was prevalent in all infertile female subjects. VD levels were strong predictor of fertility in the study population. The significant association of VD with FSH explained the indirect effect of VD on follicular development and ovarian functions however no relationship of VD with ovarian reserve was exhibited.