title: Plasma folate levels in early to mid pregnancy after a nation-wide folic acid supplementation program in areas with high and low prevalence of neural tube defects in China.
abstract: BACKGROUND
  Folic acid supplementation is recommended for all women of child-bearing age to prevent neural tube defects (NTDs). A nation-wide folic acid supplementation program was implemented in rural areas of China since 2009; however, changes in plasma folate levels in pregnant women were unknown.
  
  
  METHODS
  A cross-sectional survey was conducted in 2011 to 2012, with 1736 pregnant women enrolled, and results were compared with a previous survey in 2002 to 2004. A microbiological method was used to determine plasma folate levels. Preprogram and postprogram median plasma folate concentrations were compared while stratified by prevalence of NTDs and residence.
  
  
  RESULTS
  In the high NTD prevalence population, plasma folate concentration increased to 33.4 (18.7, 58.4) nmol/L in the postprogram sample, which is 2.9 times of the preprogram. In the low NTD prevalence population, plasma folate increased to 67.9 (44.5, 101.9) nmol/L, which is 1.9 times of the preprogram. Gaps remained in plasma folate levels with respect to prevalence of NTDs and residence. Folic acid supplementation has a strong impact on plasma folate concentrations. Earlier supplementation (before the last menstrual period), increased supplementation frequency and more total days of supplementation were associated with a higher plasma folate concentration as demonstrated in both the high- and low-prevalence populations.
  
  
  CONCLUSIONS
  Plasma folate levels among pregnant Chinese women increased dramatically after the nation-wide folic acid supplementation program in both rural and urban areas, and in populations of high and low NTD prevalence. The nation-wide program should have a component to ensure that supplementation begins before pregnancy.
authors: Institute of Reproductive and Child Health / Ministry of Health Key Laboratory of Reproductive Health; Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China.
authors: Jufen
authors: J
authors: Liu
authors: Institute of Reproductive and Child Health / Ministry of Health Key Laboratory of Reproductive Health; Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China.
authors: Lili
authors: L
authors: Gao
authors: Institute of Reproductive and Child Health / Ministry of Health Key Laboratory of Reproductive Health; Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China.
authors: Yali
authors: Y
authors: Zhang
authors: Institute of Reproductive and Child Health / Ministry of Health Key Laboratory of Reproductive Health; Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China.
authors: Lei
authors: L
authors: Jin
authors: Institute of Reproductive and Child Health / Ministry of Health Key Laboratory of Reproductive Health; Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China.
authors: Zhiwen
authors: Z
authors: Li
authors: Institute of Reproductive and Child Health / Ministry of Health Key Laboratory of Reproductive Health; Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China.
authors: Le
authors: L
authors: Zhang
authors: Institute of Reproductive and Child Health / Ministry of Health Key Laboratory of Reproductive Health; Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China.
authors: Qinqin
authors: Q
authors: Meng
authors: Institute of Reproductive and Child Health / Ministry of Health Key Laboratory of Reproductive Health; Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China.
authors: Rongwei
authors: R
authors: Ye
authors: Institute of Reproductive and Child Health / Ministry of Health Key Laboratory of Reproductive Health; Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China.
authors: Linlin
authors: L
authors: Wang
authors: Institute of Reproductive and Child Health / Ministry of Health Key Laboratory of Reproductive Health; Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China.
authors: Aiguo
authors: A
authors: Ren
mesh_terms: D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D019587:Dietary Supplements / Q000706:statistics & numerical data; D005260:Female; D005492:Folic Acid / Q000097:blood* / Q000627:therapeutic use*; D006801:Humans; D009436:Neural Tube Defects / Q000453:epidemiology* / Q000517:prevention & control*; D011247:Pregnancy; D011322:Primary Prevention / Q000379:methods* / Q000706:statistics & numerical data
chemical_list: D005492:Folic Acid
keywords: folate; folic acid supplementation; pregnancy; reproductive age; women