title: Female fetus is associated with greater maternal insulin resistance in pregnancy.
abstract: OBJECTIVE
  To explore the hypothesis that female fetus is associated with greater maternal insulin resistance during pregnancy.
  
  
  METHODS
  In a singleton pregnancy cohort study (n = 299), we compared maternal insulin resistance according to fetal sex, based on plasma biomarkers from a 50-g 1-h oral glucose tolerance test at 24-28 weeks gestation. The primary outcome was plasma glucose-to-insulin ratio. Other outcomes included plasma proinsulin-to-insulin ratio, and insulin, proinsulin, leptin, adiponectin and insulin-like growth factor I and II concentrations.
  
  
  RESULTS
  After adjusting for maternal race, age, parity, education, pre-pregnancy BMI, smoking and alcohol use, history of gestational diabetes, and gestational age at blood sampling, plasma insulin concentrations were significantly higher (mean ± sd: 66.4 ± 50.5 vs. 51.0 ± 46.1 mU/l; adjusted P = 0.001), and glucose-to-insulin ratios significantly lower (2.60 ± 2.03 vs. 3.77 ± 4.98 mg/dl/mU/l; adjusted P = 0.002) in women bearing a female vs those bearing a male fetus, despite similar glucose levels (116.4 ± 27.2 vs. 117.0 ± 31.9 mg/dl; adjusted P = 0.92).There were no significant differences in proinsulin-to-insulin ratios, or leptin, adiponectin, insulin-like growth factor I and insulin-like growth factor II concentrations by fetal sex.
  
  
  CONCLUSIONS
  Female fetus may be associated with greater maternal insulin resistance during pregnancy.
authors.affiliation: Departments of Obstetrics and Gynecology, Sainte-Justine Hospital Research Center, University of Montreal, Montreal, Canada.
authors.forename: L
authors.initials: L
authors.lastname: Xiao
authors.forename: J P
authors.initials: JP
authors.lastname: Zhao
authors.forename: A M
authors.initials: AM
authors.lastname: Nuyt
authors.forename: W D
authors.initials: WD
authors.lastname: Fraser
authors.forename: Z C
authors.initials: ZC
authors.lastname: Luo
mesh_terms: D052242:Adiponectin / Q000378:metabolism; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D005260:Female; D005333:Fetus; D005951:Glucose Tolerance Test; D006801:Humans; D007231:Infant, Newborn; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007335:Insulin-Like Growth Factor II / Q000378:metabolism; D020738:Leptin / Q000378:metabolism; D008297:Male; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology* / Q000378:metabolism; D011384:Proinsulin / Q000378:metabolism; D012737:Sex Factors
chemical_list: D052242:Adiponectin; D001786:Blood Glucose; D007328:Insulin; D020738:Leptin; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D011384:Proinsulin