Vitamin D and assisted reproduction technologies: current concepts

Abstract

Accumulating evidence from animal and human studies suggests that vitamin D is involved in many functions of the human reproductive system in both genders, but no comprehensive analysis of the potential relationship between vitamin D status and Assisted Reproduction Technologies (ART) outcomes is currently available. On this basis, the purpose of this systematic review and meta-analysis was to perform an in-depth evaluation of clinical studies assessing whether vitamin D status of patients undergoing ART could be related to cycle outcome variables. This issue is of interest considering that vitamin D deficiency is easily amenable to correction and oral vitamin D supplementation is cheap and without significant side effects. Surprisingly, no studies are currently available assessing vitamin D status among male partners of couples undergoing ART, while seven studies on vitamin D status of women undergoing controlled ovarian hyperstimulation (COH) for ART were found and included in the review. Results show that vitamin D deficiency is highly prevalent among women undergoing COH, ranging from 21% to 31% across studies conducted in Western countries and reaching 75-99% in Iranian studies. Data on vitamin D deficiency (25-hydroxyvitamin D serum levels <20 ng/ml) in relation to ART outcomes could be extracted from three studies and included in the meta-analysis, yielding a common risk ratio (RR) of 0.89 (95% CI 0.53-1.49) and showing a lower but not statistically significant likelihood of clinical pregnancy for vitamin-D-deficient women compared with vitamin-D-sufficient patients. In conclusion, there is insufficient evidence to support the routine assessment of vitamin D status to predict the clinical pregnancy rate in couples undergoing ART. The partly conflicting results of the available studies, potentially explaining the lack of statistical significance for a negative influence of vitamin D deficiency on clinical pregnancy rate, are likely secondary to confounders and insufficient sample size, and further larger cohort and randomised controlled studies are required.

Vitamin D and assisted reproduction: should vitamin D be routinely screened and repleted prior to ART? A systematic review

“…This overall prevalence of vitamin D deficiency was slightly lower than what has been reported for the general population of childbearing age women in the US (31 %) [3]. As Vanni et al [80] reported, a lower prevalence of vitamin D deficiency is to be expected in a population of women seeking IVF, as these women tend to have higher socioeconomic status as well as education level, both of which are factors associated with higher vitamin D levels. Garbedian et al [72] suggested that the low number of vitamin D deficient women reported in their study (1.2 %) was due to increased usage of daily prenatal vitamins.…”

Prepregnancy Nutrition and Early Pregnancy Outcomes

“…Since then the number of publications on this topic has grown with heterogeneous results [54]. The second study published on this association actually observed a negative effect of increasing follicular fluid vitamin D levels on IVF outcomes [55].…”

Role of sunshine vitamin &#147;D&#148; sufficiency in male and female infertility

“…Studies have shown that vitamin D deficiency is highly prevalent among women undergoing Controlled Ovarian Stimulation (COS) in Assisted Reproductive Technology (ART) procedures. 18 In women, vitamin D deficiency status has been associated with less IVF outcome, features of PCOS, and endometriosis. 4 Vitamin D has direct effect on Anti Mullarian Hormone (AMH) production, and thus increases longer maintenance of ovarian reserve in the patients with its higher concentration.…”