Zhang Y, He X, Xiong X, Chuan J, Zhong L, Chen G, Yu D. The association between maternal methylenetetrahydrofolate reductase C677T and A1298C polymorphism and birth defects and adverse pregnancy outcomes. Prenat Diagn. 2019 Jan;39(1):3–9. doi: 10.1002/pd.5396. PMID: 30474229.