Vitamin D and Anti-Müllerian Hormone Levels in Infertility Treatment: The Change-Point Problem.

Background: Anti-Müllerian hormone (AMH) is considered to be one of the most significant indicators of women's fertility. Many studies have shown that vitamin D may modify human reproductive functions; however, the results are conflicting. The composition of follicular fluid (FF) creates the biochemical environment of the oocyte and affects its quality, which later determines the embryo quality. In this study, we aimed to revise with advanced statistical techniques the relationship between AMH and vitamin D in FF.

Methods: The study was designed as a prospective single-center study in infertile patients with AMH ≥ 0.7 ng/mL who underwent controlled ovarian hyperstimulation for in vitro fertilization. AMH and vitamin D levels in FF were measured. Next, the standard and advanced statistical (including segmented regression) techniques were applied.

Results: We observed a negative linear correlation between levels of AMH in serum and FF and total vitamin D concentrations up to approximately 30 ng/ml; with a statistically significant relationship in FF. Beyond that concentration, the trend was positive but statistically insignificant.

Conclusions: As an existing "change-point problem" was noticed, we suggest segmentation in the relationship between vitamin D and AMH during infertility treatment.