Maternal MTHFR C677T polymorphism does not affect live birth rate following IVF in Chinese Han population: a retrospective cohort study of 1265 women
Abstract Backgrounds: MTHFR is a key enzyme for folic acid metabolism and is important for reproduction. However, whether MTHFR C677T genotype affect live birth rate following IVF is unknown. This study aims to evaluate the association of MTHFR C677T polymorphism and live birth rate following IVF. Methods: This is a retrospective cohort study of 1265 women undergoing first IVF -ET cycle (2015-2017) in Reproductive Medicine Center of Xiangya Hospital. The patients were followed for a minimum of 2 years and maximum of 5 years, the observation endpoint is live birth, or all the embryos derived from the first stimulation cycle are transferred. The study population was divided into three groups based on MTHFR C677T genotype (MTHFR 677CC, MTHFR 677CT, MTHFR 677TT). The primary outcomes are live birth rate and cumulative live birth. The secondary outcomes including laboratory parameters (number of oocytes, number of 2PNs, number of available embryos, number of good embryos) and clinical parameters (chemical pregnancy rate, clinical pregnancy rate, implantation rate, preclinical pregnancy loss rate, miscarriage rate). The logistic regression analysis with different adjusted models were used to analyze the association of MTHFR C677T genotype and live birth. Results: Among the 1265 participants, 541 were MTHFR 677CC genotype, 585 were MTHFR 677CT genotype, and 139 were MTHFR 677TT genotype. The live birth rate was 43.6%, 44.8%, and 40.3% (p-value = 0.63), and the cumulative live birth rate per stimulation cycle was 54.7%, 53.5%, and 51.8% (p-value =0.81) in MTHFR 677CC group, MTHFR 677CT group, and MTHFR 677TT group, respectively. The secondary laboratory outcomes and clinical outcomes were not significantly different between the three groups. Logistic regression analysis showed no significant association of MTHFR C677T genotype and live birth whether in model 1 (p-value for trend = 0.63) , model 2 (p-value for trend = 0.63), or model 3 (p-value for trend = 0.59). Conclusions: MTHFR C677T genotype does not significantly affect live birth rate and cumulative live birth rate following first IVF in Chinese Han couples.