Vitamin D in Follicular Fluid Correlates With the Euploid Status of Blastocysts in a Vitamin D Deficient Population

Context The widespread distribution of the Vitamin D (VitD) receptor in reproductive tissues suggests an important role for VitD in human reproduction. The assessment of patient ' s VitD is based on the 25-hydroxyvitamin D (25(OH)D) metabolite measurement. However, most of the circulating 25(OH)D is bound to either VitD-binding protein (VDBP) (88%) or albumin (12%) and less than 1% circulates free. Objective To determine a possible correlation between VitD levels in serum (S) and follicular fluid (FF) and blastocyst ploidy status in patients undergoing infertility treatment. Methods A prospective observational study was performed including couples planned for preimplantation genetic testing for aneuploidies (PGT-A) from ART Fertility Clinics. Patients were classified according to their 25(OH)D-Serum levels: VitD deficient group Results Serum samples and 226 FF from individual follicles were collected for 25(OH)D, bioavailable 25(OH)D, free 25(OH)D, and % free 25(OH)D measurement. 25(OH)D-Serum in VitD deficient and non-deficient were 13.2 +/- 4.0 ng/ml vs 32.3 +/- 9.2 ng/ml; p<0.001. FF from 40 and 74 biopsied blastocysts was analysed of which 52.5 and 60.8% were euploid (p = 0.428), respectively. In VitD deficient patients, mean 25(OH)D-FF, bioavailable 25(OH)D-FF, and free 25(OH)D-FF were higher in euploid vs aneuploid blastocysts (18.3 +/- 6.3 ng/ml vs 13.9 +/- 4.8 ng/ml; p = 0.040; 1.5 +/- 0.5 ng/ml vs 1.1 +/- 0.4 ng/ml; p = 0.015; 0.005 +/- 0.002 ng/ml vs 0.003 +/- 0.001 ng/ml; p = 0.023, respectively), whilst no differences were found in VitD non-deficient patients (37.9 +/- 12.3 ng/ml vs 40.6 +/- 13.7 ng/ml; p = 0.380; 3.1 +/- 1.1 ng/ml vs 3.3 +/- 1.2 ng/ml; p = 0.323; 0.01 +/- 0.003 ng/ml vs 0.01 +/- 0.004 ng/ml; p = 0.319, respectively). Conclusion VitD non-deficient patients have a significantly higher probability of obtaining a euploid blastocyst compared to VitD deficient patients (OR:33.36, p = 0.002).

Automated summary

The widespread presence of the Vitamin D receptor in reproductive tissues indicates an important role for Vitamin D in human reproduction. This study found that patients with insufficient levels of Vitamin D had a significantly lower likelihood of obtaining euploid blastocysts during infertility treatment.