title: Association of methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism with preterm delivery and placental abruption: a systematic review and meta-analysis.
abstract: BACKGROUND
  The aim of this study was to summarize evidence on the association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and odds of preterm delivery and placental abruption.
  
  
  METHODS
  PubMed, EMBASE, CBM (Chinese Biomedical Database) and CNKI (Chinese National Knowledge Infrastructure) were searched to identify eligible studies published in English or Chinese before 12 August 2014. The pooled odds ratios (ORs) with 95% confidence intervals were estimated for the association of MTHFR C677T polymorphism with preterm delivery and placental abruption using random effects models.
  
  
  RESULTS
  A total of 22 studies that met inclusion and exclusion criteria were included in this meta-analysis. Regardless of the genetic model tested we found no statistically significant association of MTHFR C677T polymorphism with preterm delivery or placental abruption. Funnel plots inspections, Begg's test and Egger's test did not show evidence of publication bias.
  
  
  CONCLUSIONS
  This meta-analysis demonstrated that overall there was no association of MTHFR C677T polymorphism with preterm delivery or placental abruption.
authors.affiliation: Medical Department, Ningbo Women and Children's Hospital, Ningbo, Zhejiang, China.
authors.forename: Jian
authors.identifier: http://orcid.org/0000-0002-0009-3134
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Obstetrics and Gynecology, Ningbo Women and Children's Hospital, Ningbo, Zhejiang, China.
authors.forename: Liang
authors.identifier: http://orcid.org/0000-0002-7171-1892
authors.initials: L
authors.lastname: Chen
authors.affiliation: Medical Department, Ningbo Women and Children's Hospital, Ningbo, Zhejiang, China.
authors.forename: Li-Hua
authors.identifier: http://orcid.org/0000-0002-3790-2636
authors.initials: LH
authors.lastname: Zhu
authors.affiliation: Department of Obstetrics and Gynecology, Ningbo Women and Children's Hospital, Ningbo, Zhejiang, China.
authors.forename: Si-Tong
authors.identifier: http://orcid.org/0000-0003-2609-8264
authors.initials: ST
authors.lastname: Zhang
authors.affiliation: Department of Epidemiology and Statistics, School of Public Health, Anhui Medical University, Hefei, Anhui, China.
authors.forename: Yi-Le
authors.identifier: http://orcid.org/0000-0003-0153-4904
authors.initials: YL
authors.lastname: Wu
mesh_terms: D000037:Abruptio Placentae / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide; D011247:Pregnancy; D047928:Premature Birth / Q000235:genetics*
chemical_list: D042965:Methylenetetrahydrofolate Reductase (NADPH2)
keywords: MTHFR; Meta-analysis; methylenetetrahydrofolate reductase; placental abruption; preterm delivery