Vitamin D and follicular recruitment in the in vitro fertilization cycle.

Objective: Vitamin D (VD) is a fat-soluble steroid hormone, synthesized by the skin, most known for its role in bone mineral balance. Vitamin D receptors (VDR) are also found in the female reproductive system, but their role remains unclear. The objective of this study was to analyze the relationship between serum vitamin D levels and the number of oocytes retrieved after ovarian stimulation.