title: Prevention of NTDs with periconceptional multivitamin supplementation containing folic acid in China.
abstract: BACKGROUND
  Maternal nutritional factors seem to contribute substantially to the complex etiologies of NTDs. Foremost among these factors is the periconceptional use of supplementation containing folic acid, which is associated with a reduction in the risk of women having NTD-affected pregnancies. This study was designed to observe the effectiveness of multivitamin supplementation containing folic acid in preventing NTDs in a Chinese population and to detect factors that would impact the effectiveness.
  
  
  METHODS
  Through family planning networks, a population-based community intervention study was carried out in 18 counties of China. Participants were divided into an intervention (taking multivitamin) group and a control group, and were followed up according to periconceptional multivitamin supplementation (in general 6 mg) for 2 years. Women who had a pregnancy were followed up from 28 weeks gestation at least to pregnancy termination, and the outcome was recorded. The incidence rate of the two groups and the relative risks were calculated to evaluate the efficacy of the multivitamin supplement in preventing NTDs.
  
  
  RESULTS
  During 2000 and 2002, all of the women having pregnancies with birth defects and women whose pregnancies were without any birth defects were interviewed. Nine NTDs were recorded from 25,444 pregnancies (NTD birth prevalence = 0.35/1,000 pregnancies) in the intervention group and 48 NTDs among 26,599 pregnancies (NTD birth prevalence = 1.80/1,000 pregnancies) in the control group. The protective rate was 80.4%.
  
  
  CONCLUSIONS
  Periconceptional multivitamin supplementation containing folic acid can prevent the occurrence of NTDs with the beneficial effect dependent on the frequency and timing of the supplementation. Our study suggests that multivitamin supplement containing folic acid taken from a time point of 2 months before conception and continuing until completion of the second month after conception and taken more than five times per week can significantly reduce the risks of NTDs.
authors.affiliation: Institute of Population Research/WHO Collaborating Center on Reproductive Health and Population Science, Peking University, Beijing 100871, China.
authors.forename: Gong
authors.initials: G
authors.lastname: Chen
authors.forename: Xinming
authors.initials: X
authors.lastname: Song
authors.forename: Ying
authors.initials: Y
authors.lastname: Ji
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Lijun
authors.initials: L
authors.lastname: Pei
authors.forename: Jiapeng
authors.initials: J
authors.lastname: Chen
authors.forename: Jufen
authors.initials: J
authors.lastname: Liu
authors.forename: Chengfu
authors.initials: C
authors.lastname: Li
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Zheng
mesh_terms: D000328:Adult; D002681:China; D019587:Dietary Supplements; D005260:Female; D005492:Folic Acid / Q000627:therapeutic use*; D005500:Follow-Up Studies; D006801:Humans; D009436:Neural Tube Defects / Q000453:epidemiology / Q000517:prevention & control*; D010349:Patient Compliance; D011159:Population Surveillance / Q000379:methods; D016742:Preconception Care / Q000379:methods; D011247:Pregnancy; D015995:Prevalence; D016896:Treatment Outcome; D014815:Vitamins / Q000627:therapeutic use
chemical_list: D014815:Vitamins; D005492:Folic Acid