Impact of the one-carbon metabolism on oocyte maturation, fertilization, embryo quality, and subsequent pregnancy.

PURPOSE

To investigate impact of the one-carbon metabolism (OCM) on oocyte maturity and embryo development.

METHODS

This prospective study analyzed 18 women who agreed to participate. We measured the OCM biomarkers' concentrations including Vitamin B12 (VB12), folic acid (FA), and homocysteine (Hcy) in serum and follicular fluid (FF), and assessed their correlation. We also evaluated the influence of such OCM biomarker concentrations in mono-FF on oocyte maturation, fertilization, embryo quality, and consequent pregnancy after embryo transfers.

RESULTS

All biomarkers showed a high concentration variability in different follicles of each woman, but their mean levels correlated with the serum levels. Among the 106 collected oocytes, 92 were mature, 59 were fertilized, and 16 yielded good-quality embryos. We performed 26 single embryo transfers, and 7 patients achieved clinical pregnancies. VB12 concentration (FF) was significantly lower in fertilized than unfertilized oocytes by univariate analysis. In multivariate logistic analysis, a significant correlation was found between FA concentration (FF) <14.25 ng/mL and good-quality embryos and between Hcy concentration (FF) <4.9 nmol/mL and clinical pregnancy.

CONCLUSION

OCM in FF may affect fertilization, embryo quality, and clinical pregnancy.