title: Maternal obesity and familial history of diabetes have opposing effects on infant birth weight in women with mild glucose intolerance in pregnancy.
abstract: OBJECTIVE
  Pregnant women with an abnormal screening glucose challenge test (GCT) but without gestational diabetes mellitus (GDM) on subsequent oral glucose tolerance test (OGTT) are at increased risk of delivering macrosomic and large for gestational age (LGA) neonates. We thus sought to evaluate the maternal constitutional and biochemical factors that determine infant birth weight in this patient population.
  
  
  METHODS
  Women with an abnormal GCT were evaluated at the time of their OGTT in late pregnancy. This analysis was restricted to Caucasian women without GDM (N = 86). Maternal demographic and biochemical factors were evaluated in relation to infant birth weight and LGA.
  
  
  RESULTS
  After adjustment for length of gestation, birth weight was positively associated with pre-pregnancy body mass index (BMI) (r = 0.31, p = 0.0063) and negatively correlated with maternal serum levels of the insulin-sensitizing protein adiponectin (r = -0.30, p = 0.0084). On multiple linear regression analysis, pre-pregnancy BMI and weight gain in pregnancy were positive independent determinants of infant birth weight, while family history of diabetes emerged as a negative independent correlate. Logistic regression analysis confirmed that pre-pregnancy BMI was a positive predictor of LGA (odds ratio (OR) = 1.25, 95% confidence interval (CI) 1.05-1.49), whereas family history of diabetes was again identified as a negative determinant (OR = 0.10, 95% CI 0.02-0.59). In contrast, neither measures of glycemia nor insulin resistance/sensitivity were independently associated with birth weight or LGA.
  
  
  CONCLUSIONS
  In pregnant women with an abnormal GCT but without GDM, pre-gravid maternal obesity predicts increased infant birth weight, whereas family history of diabetes is independently associated with decreased infant size.
authors.affiliation: Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Phillip
authors.initials: P
authors.lastname: Segal
authors.forename: Jill K
authors.initials: JK
authors.lastname: Hamilton
authors.forename: Mathew
authors.initials: M
authors.lastname: Sermer
authors.forename: Philip W
authors.initials: PW
authors.lastname: Connelly
authors.forename: Anthony J G
authors.initials: AJ
authors.lastname: Hanley
authors.forename: Bernard
authors.initials: B
authors.lastname: Zinman
authors.forename: Ravi
authors.initials: R
authors.lastname: Retnakaran
mesh_terms: D000328:Adult; D001724:Birth Weight; D003920:Diabetes Mellitus / Q000235:genetics; D016640:Diabetes, Gestational; D005260:Female; D005320:Fetal Macrosomia; D020022:Genetic Predisposition to Disease; D018149:Glucose Intolerance; D005951:Glucose Tolerance Test; D006801:Humans; D007231:Infant, Newborn; D009765:Obesity; D016017:Odds Ratio; D011247:Pregnancy