title: A case-control study of the effects of pregnancy planning on neural tube defects and its primary preventive measures.
abstract: BACKGROUND
  Measures for prevention of neural tube defects (NTDs) have been recommended for many years in China, but the compliance with these measures is unsatisfactory. This study aims to compare the effect differences between planned pregnancy and unplanned pregnancy in the compliance with these measures and analyze the interactions between pregnancy planning and these measures for NTD prevention.
  
  
  METHODS
  A 1:1 matched case-control study was conducted. We randomly selected 349 women who delivered or gestated babies/fetuses with NTDs in the last two years in two provinces and matched them with 349 women who delivered babies without obvious birth defects as controls.
  
  
  RESULTS
  In the case group, 99 women reported that they had planned their pregnancies, accounting for 28.4%, and the proportion who received preconception examinations and took folic acid prior to conception was 13.8 and 8.6%, respectively. According to the multivariate analysis, health education (odds ratio [OR], 0.350), preconception examinations (OR, 0.497) and folic acid consumption prior to conception (OR, 0.257) all had preventative effects on NTDs (for all, p < 0.05). In both groups, the proportions of women who received preconception examinations and reported folic acid intake were much higher for those who reported planning their pregnancies compared to women with an unplanned pregnancy (for all, p < 0.01); and for NTD prevention, synergistic interactions existed between pregnancy planning and the other preventive measures.
  
  
  CONCLUSIONS
  Folic acid consumption prior to conception, preconception examinations, and health education have preventive effects on NTDs. Pregnancy planning can significantly promote compliance with these preventive behaviors. In addition, there are synergistic interactions between pregnancy planning and these measures.
authors.affiliation: Department of Epidemiology and Health Statistics, School of Public Health, Shandong University, Jinan, Shandong, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Gong
authors.forename: Zhi-Ping
authors.initials: ZP
authors.lastname: Wang
authors.forename: Li-Jie
authors.initials: LJ
authors.lastname: Gao
authors.forename: Qing-Bin
authors.initials: QB
authors.lastname: Lu
authors.forename: Xi-Hong
authors.initials: XH
authors.lastname: Sun
authors.forename: Zhong-Tang
authors.initials: ZT
authors.lastname: Zhao
mesh_terms: D016022:Case-Control Studies; D002681:China; D003267:Contraception / Q000009:adverse effects; D019587:Dietary Supplements; D005193:Family Planning Services; D005260:Female; D005492:Folic Acid / Q000627:therapeutic use*; D015438:Health Behavior; D006801:Humans; D009436:Neural Tube Defects / Q000517:prevention & control*; D016742:Preconception Care; D011247:Pregnancy; D049168:Pregnancy, Unplanned; D011275:Pregnancy, Unwanted; D011295:Prenatal Care; D014815:Vitamins / Q000627:therapeutic use
chemical_list: D014815:Vitamins; D005492:Folic Acid