| Objectives1.To analysis serum folate and vitamin B12 concentrations during pregnancy in pregnant women who were local residents in Guangxi.2.To explore the influence of maternal serum folate and vitamin B12(B12)status during pregnancy on the incidence of low birth weight(LBW)infant.Study design and MethodsA total of 6,203 eligible women registered in eight hospitals from Guangxi,Chinese Between July 2015 and September 2015.A face-to-face interview was conducted by trained physicians to get the basic information of each participant and collected their blood samples.Then followed the delivery information including infants’birth weight,gestational age,gender,etc.Until June 2016,after excluded multiple birth,unknown infant gender,abortion,stillbirth and birth defect,then there are 230 cases with singleton live births and 382 controls were matched for further analyses.Gestational ages were calculated from the first day of the last menstrual period.Infants were considered LBW when the birth weight<2500 g.Concentration of serum folate and B12 were detected with CMIA(chemiluminescence microparticle immunoassay)on ARCHITECT i2000-1.According to the control group of the first trimester,second trimester and third trimester,maternal folate and B12 levels were divided into four quantiles in every pregnancy age,respectively.Epidata3.1 was used to record data,and SPSS 17.0 was used to analyze the data.The percentage rates were evaluated using chi-square(?~2)test,and the non-normal variables were assessed with the Mann-Whitney U test and Kruskal-Wallis one-way ANOVA test.According to the control group,the folate and B12 levels were divided into four quartiles,respectively,by the three trimesters of pregnancy.Binary logistic regression was used to evaluate the effects of folate and B12 levels on LBW.Statistical tests were two-sided,?=0.05 and the P-value<0.05 was defined as statistically significant.ResultsA total of 6,203 eligible women were included in our study,and 5541women were followed up to pregnancy outcomes.In our study,362 births with low birth weight,so the incidence of low birth weight infants was 6.53%.In low birth weight infants,premature low birth weight infants accounted for 55.1%,and term low birth weight infants accounted for 44.9%.Maternal serum folate levels increased basically with increasing the period of folic acid supplementation(P-trend<0.001).maternal serum folate and B12 levels gradually decreased with the increase of gestational age(P<0.001).Compared with the women in their highest folate quartile,the women in the lowest quartile of folate achieved an unadjusted OR of 2.20(95%CI:1.21-3.99,P=0.010)for LBW in model 1.The OR of folate was 2.44(95%CI:1.32-4.54 and P=0.005)after adjusting for BMI,gravida,parity,smoking status and alcohol drinking in model 2.After further adjusted the folic acid supplementation status before 1moth pregnancy and pregnancy and LBW delivery in previous in model 3,the OR of folate was 2.51(95%CI:1.31-4.80 and P=0.006).However,no significant association was observed between serum folate and LBW in the first trimester or third trimester.In addition,serum B12 exhibited no significant association with LBW.ConclusionThe incidence of low birth weight in the current Guangxi population was6.53%.Maternal serum folate and B12 levels gradually decreased with the increase of gestational age.Low serum folate levels(<7.0 ng/mL)in the second trimester significantly increases the risk of LBW amongst Chinese women with singleton pregnancies. |
PDF Full Text Request