title: Unexpected relationship between plasma homocysteine and intrauterine growth restriction.
abstract: BACKGROUND
  Moderate hyperhomocysteinemia is considered a risk factor for thrombosis and atherosclerosis. We hypothesized that higher maternal and newborn homocysteine concentrations in plasma would increase the risk of intrauterine growth restriction through placental thrombosis.
  
  
  METHODS
  We carried out a case-control study that included all cases born at our institution over a 2-year period whose birthweight was below the 10th percentiles for gestational age and sex according to Canadian norms; controls were born at the same period and institution at or above the 10th percentiles and were matched on gestational age, race, and sex. Homocysteine was measured in cord and maternal blood. The analysis included 483 case and 468 control mothers and 409 case and 438 control newborns.
  
  
  RESULTS
  Homocysteine values were largely <15 micromol/L. Contrary to expectation, within that range of values, increased plasma homocysteine, particularly in the mother, was protective against intrauterine growth restriction. With the case/control status as the outcome, the estimated odds ratio was 0.37 (95% confidence interval, 0.24-0.58) for a 5 micromol/L unit difference on the maternal homocysteine scale. With birthweight as the outcome, the estimated increase was 178.1 g (95% confidence interval, 92.5-263.7 g) for every 5 micromol/L unit increase in maternal homocysteine. Results were similar using newborn homocysteine concentrations.
  
  
  CONCLUSIONS
  The data suggest that, in contrast to the proposed hypothesis, mothers with small babies have lower homocysteine concentrations than those giving birth to larger ones.
authors.affiliation: Department of Epidemiology, Biostatistics, and Occupational Health, Faculty of Medicine, McGill University, Montréal, Province of Québec, H3A 1A3 Canada. claire.infante-rivard@mcgill.ca
authors.forename: Claire
authors.initials: C
authors.lastname: Infante-Rivard
authors.forename: Georges-Etienne
authors.initials: GE
authors.lastname: Rivard
authors.forename: Robert
authors.initials: R
authors.lastname: Gauthier
authors.forename: Yves
authors.initials: Y
authors.lastname: Théorêt
mesh_terms: D016022:Case-Control Studies; D005260:Female; D005312:Fetal Blood; D005317:Fetal Growth Retardation / Q000097:blood / Q000175:diagnosis*; D005865:Gestational Age; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D008297:Male; D042965:Methylenetetrahydrofolate Reductase (NADPH2); D009035:Mothers; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000235:genetics; D011110:Polymorphism, Genetic
chemical_list: D006710:Homocysteine; D000587:Oxidoreductases Acting on CH-NH Group Donors; D042965:Methylenetetrahydrofolate Reductase (NADPH2)