title: The effectiveness of prenatal serum biomarker screening for neural tube defects in second trimester pregnant women: a meta-analysis.
abstract: BACKGROUND
  Neural tube defects (NTDs) are common and serious birth defects all over the world. Prenatal screening for NTDs using maternal serum alpha-fetoprotein (MSAFP) during the second trimester of pregnancy has been widely used, but its effectiveness remains unclear.
  
  
  METHODS
  We evaluated the studies published in the English and Chinese on MSAFP screening for NTDs. The homogeneity of the studies was evaluated by the forest graph. Meta-analysis was applied to calculate the combined effect values and their 95% confidence intervals.
  
  
  RESULTS
  As many as 22 articles were selected according to the criteria and were included in the meta-analysis, for a total of 684,140 pregnant women screened during the second trimester. All the studies selected were homogenous according to the forest graph (chi(2) = 25.17, P > 0.10). The combined relative risk estimate was 0.25 and its 95% confidence interval was 0.21 to 0.29. The combined protective rate was 75%. The sensitivity and specificity of MSAFP screening were 75.1 and 97.7%, respectively.
  
  
  CONCLUSIONS
  Use of MSAFP during the second trimester in pregnant women is an effective measure for the screening of NTDs.
authors.affiliation: Department of Epidemiology and Health Statistics, School of Public Health, Shandong University, Jinan, Shandong, China. zhiping9312@yahoo.cn
authors.forename: Zhi-Ping
authors.initials: ZP
authors.lastname: Wang
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Lian-Zheng
authors.initials: LZ
authors.lastname: Hao
authors.forename: Zhong-Tang
authors.initials: ZT
authors.lastname: Zhao
mesh_terms: D015982:Bias; D015415:Biomarkers / Q000097:blood*; D001774:Blood Chemical Analysis / Q000379:methods / Q000592:standards; D004526:Efficiency; D005260:Female; D006801:Humans; D008403:Mass Screening / Q000379:methods; D009436:Neural Tube Defects / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology; D011237:Predictive Value of Tests; D011247:Pregnancy; D011262:Pregnancy Trimester, Second / Q000097:blood*; D011296:Prenatal Diagnosis / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers