Objective: Vitamin D has several metabolic functions and possible reproductive functions. This study aimed to determine the prevalence of vitamin D deficiency among Brazilian women of reproductive age, and to evaluate the relationship between serum 25-hydroxyvitamin D [25(OH)D] concentrations and infertility causes.
Subjects and methods: This retrospective cross-sectional study evaluated data from a private Brazilian assisted reproduction center that were collected between January 1 and May 5, 2012. Serum 25(OH)D concentrations were measured and compared for infertile and fertile women. Concentrations of 25(OH)D that were < 20 ng/mL were defined as deficiency and concentrations of 21-30 ng/mL were defined as hypovitaminosis D.
Results: Among the 369 evaluated women, 81.1% exhibited hypovitaminosis D and 32.0% exhibited deficiency. The infertile and control patients did not exhibit any significant differences in the prevalence of vitamin D deficiency (30.2% vs. 35%, respectively; p = 0.33) or in the mean 25(OH)D concentrations (24.3 ± 7.9 ng/mL vs. 23.8 ± 8.7 ng/mL, respectively; p = 0.51). Furthermore, there were no significant differences in the mean 25(OH)D concentrations among subgroups of patients with single infertility factors, or between these subgroups and the control group.
Conclusions: A high proportion of Brazilian women of reproductive age exhibited vitamin D deficiency, regardless of their fertility status. Thus, it may be useful to evaluate this population for vitamin D deficiency, although future studies are needed to determine whether this deficiency might affect the outcomes of treatments for infertility.