Abstract：Objective To investigate the effect of MTHFR and MTRR gene polymorphisms on preterm delivery, and to provide theoretical basis for preterm delivery intervention.Methods In this case-control study, 162 cases of premature infants delivered in Maternal and Child Health Hospital of Gansu Province from May 2017 to August 2018 were selected as the case group, and 162 cases of normal gestational age newborns born in this hospital at the same period were selected as the control group, The epidemiological and clinical data of the two groups were collected by questionnaire. Univariate analysis of statistically significant factors were included in multivariate logistic analysis α 0.05 as the test level.Results Multivariate Logistic regression analysis showed that registered residence in rural areas (OR=2.65, 95% CI=1.31-5.38), local residents living in Lanzhou (OR=3.55, 95% CI=2.00-6.30), pregnancy induced hypertension (OR=6.42, 95% CI=1.71-24.13), assisted reproductive technology (OR=10.87, 95% CI=2.85-41.52) were risk factors for premature delivery. 3 months before pregnancy (or = 0.07, 95% CI = 0.02-0.29), 3-6 months of pregnancy (OR=0.14, 95% CI=0.04-0.47) and more than 6 months of pregnancy (OR=0.16, 95% CI=0.06-0.44) were protective factors for preterm delivery. According to the MTHFR and MTRR gene risk level assessment, MTHFR and MTRR gene polymorphisms were moderate risk group and high risk group, and whether pregnant women took folic acid supplementation also had statistical significance on premature delivery outcome (P<0.05).Conclusion Rural household registration, local living in Lanzhou, pregnancy and pregnancy-induced hypertension is a risk factor for preterm birth.Folic acid supplementation for 3 months before pregnancy and more than 6 months before pregnancy are protective factors for folic acid during pregnancy. Folic acid should be selected individually according to different genotypes during before and pregnancy. The higher the genetic risk level, the longer the duration of folic acid supplementation should be extended to 3 months before pregnancy and 6 months during pregnancy.
