Figure. Dose-Response Association of Maternal Levels of Folate, Vitamin B₁₂, and Homocysteine With Congenital Heart Disease (CHD) Risk in Offspring.

The nonlinear associations between maternal serum levels of folate and CHD risk in offspring were examined using conditional logistic regression including a restricted cubic spline term for levels of folate, vitamin B₁₂, and homocysteine with adjustment for maternal periconceptional folic acid supplementation, education, occupation, parity, abortion history, pregnancy with diabetes, pregnancy with hypertension, pregnancy with cardiac diseases, infection, in vitro fertilization and embryo transfer, and 5,10-methylenetetrahydrofolate reductase (MTHFR) 677, MTHFR 1298, and 5-methyltetrahydrofolate-homocysteine methyltransferase reductase 66 polymorphisms. Orange lines represent the regression line and shaded areas indicate 95% CIs. OR indicates odds ratio.