title: Methylenetetrahydrofolate reductase C677T polymorphism and the risk of unexplained recurrent pregnancy loss: a meta-analysis.
abstract: OBJECTIVE
  To investigate the association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and the risk of unexplained recurrent pregnancy loss (URPL).
  
  
  METHODS
  Meta-analysis of published case-control studies of the MTHFR C677T variant and URPL risk.
  
  
  METHODS
  A research institution in China.
  
  
  METHODS
  Women with URPL.
  
  
  METHODS
  None.
  
  
  METHODS
  Odds ratios (ORs) and 95% confidence intervals (CIs) for TT versus CC genotype, CT versus CC genotype, TT versus CT and CC genotype combined, and for T versus C allele.
  
  
  RESULTS
  Twenty-six studies with 2120 URPL cases and 2949 controls were included. Overall random-effects ORs of 1.49 (95% CI, 1.12-2.00) for TT versus CC genotype, 1.40 (95% CI, 1.11-1.77) for TT versus CT and CC genotype combined, and 1.21 (95%CI, 1.04-1.40) for T versus C allele were found. Stratified analysis showed that significant strong associations between MTHFR C677T polymorphism and URPL were present only in the five Chinese studies (OR = 2.96 for TT versus CC genotype; OR = 2.30 for TT versus CT+CC genotype; OR = 1.73 for T versus C allele), but not in any other studies, including the studies conducted in the European countries.
  
  
  CONCLUSIONS
  The MTHFR C677T mutation is not a genetic risk factor for URPL except in a Chinese population.
authors.affiliation: Institute of Reproductive and Child Health, Peking University Health Science Center, Beijing, China. renag@sohu.com <renag@sohu.com>
authors.forename: Aiguo
authors.initials: A
authors.lastname: Ren
authors.forename: Juan
authors.initials: J
authors.lastname: Wang
mesh_terms: D000026:Abortion, Habitual / Q000453:epidemiology* / Q000235:genetics*; D000328:Adult; D002681:China / Q000453:epidemiology; D005260:Female; D020022:Genetic Predisposition to Disease / Q000453:epidemiology / Q000235:genetics; D005820:Genetic Testing / Q000379:methods; D006801:Humans; D015994:Incidence; D038622:Internationality; D016239:MEDLINE; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics*; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011247:Pregnancy; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors
chemical_list: D042965:Methylenetetrahydrofolate Reductase (NADPH2)