Background: Infertility is a unique medical condition because it involves a couple, rather than a single individual. It is defined as inability of a couple to conceive after 12 months of regular intercourse without use of contraception in women less than 35 years of age; and after six months of regular intercourse without use of contraception in women 35 years and older. Vitamin D has profound effects on many biological systems, including the reproductive system. The spectrum of Vitamin D target organs has expanded and the reproductive role of Vitamin D is highlighted by expression of the Vitamin D receptor (VDR) and enzymes that metabolise Vitamin D in testis, the male reproductive tract and human spermatozoa.
Aim: To assess the association between serum level of Vitamin D and pregnancy outcome in women with unexplained infertility undergoing an induction of ovulation.
Materials and Methods: This is a cohort study was conducted at Ain Shams University Maternity Hospital (infertility clinic) in a period of 6 months from June 2019 to November 2019. The population of this study was women with unexplained infertility in childbearing period, normal husband semen analysis, regular menstrual cycle, normal transvaginal ultrasonography, normal HSG and/or laparoscopy with chromotubation and normal hormonal profile for FSH, LH, Prolactin and thyroid gland.
Results: The vitamin D level was significantly higher in pregnant women than non pregnant. After adjustment for the effect of other variables, there was no statistically significant relation between vitamin D level and chemical pregnancy. On the other hand, secondary infertility was an independent predictor of chemical pregnancy. Our results showed that vitamin D level has limited predictive value with an area under the ROC curve (AUC) of 0.621. The best cutoff is a value of >32.5 ng/mL, which has a sensitivity of 28% and specificity of 95%. There is weak negative correlation between serum vitamin D and LH level. Lastly, after adjustment for the effect of other variables, adequate vitamin D and secondary infertility were an independent predictors of chemical pregnancy. There was significantly high rate of positive chemical pregnancy test among women had sufficient serum vitamin D when compared to those had deficient/ insufficient serum vitamin D.
Conclusion: There was no statistically significant relation between vitamin D level and pregnancy outcome in women with unexplained infertility undergoing induction of ovulation. Moreover, our results showed that vitamin D level has limited predictive value in women with unexplained infertility undergoing induction of ovulation, the best cutoff value was >32.5 ng/mL. After adjustment for the effect of other variables, adequate vitamin D was an independent predictors of chemical pregnancy.