title: Obesity, maternal smoking and SHBG in neonates.
abstract: BACKGROUND
  Sex hormone binding globulin (SHBG), a glycoprotein produced by hepatocytes that transports testosterone and other steroids in plasma, is a marker for developing metabolic syndrome and T2DM. SHBG is present in umbilical cord blood where it may be epigenetically regulated. This study was conducted to investigate whether the fetal environment, based on maternal pre-pregnancy weight, pregnancy weight gain or smoking during pregnancy, influence SHBG in newborns.
  
  
  METHODS
  Maternal and newborn characteristics and SHBG levels and other variables were measured in cord and day 2 heel-stick blood samples in 60 healthy full-term singleton babies (31 F, 29 M).
  
  
  RESULTS
  SHBG levels varied nearly fivefold among male and female newborns and were unrelated to sex, neonatal adiposity, determined by the Ponderal index and skinfold thickness, nor TNF∝ in cord blood. There were also no statistically significant associations between pre-pregnancy weight or pregnancy weight gain and newborn SHBG levels. However, cord blood SHBG was higher and insulin levels were lower when mothers were smokers, but normalized by day 2.
  
  
  CONCLUSIONS
  While SHBG levels are low in obese children and adults, and portend the development of metabolic syndrome and T2DM, our study of healthy babies born to normal women, found no connection between maternal obesity or newborn adiposity and SHBG levels in newborns. Insofar as women who smoked during pregnancy were thinner and had lower cord blood insulin levels than nonsmokers, higher SHBG in their newborns at birth might have been due to insulin sensitivity, or perhaps to an effect of smoking on placental gene expression.
  
  
  CONCLUSIONS
  Factors other than maternal weight and pregnancy weight gain appear to be the major determinants of SHBG in newborns. Higher SHBG levels when mothers smoke during pregnancy may contribute to overweight beginning later in childhood. Whether newborn SHBG levels predict the development of overweight and metabolic syndrome remains to be determined.
authors.affiliation: Division of Endocrinology, Metabolism and Diabetes, University of Louisville, ACB-A3G11, 550 Jackson Street, Louisville, KY 40202 USA.
authors.forename: Swapna
authors.initials: S
authors.lastname: Dharashivkar
authors.affiliation: Department of Pediatrics, University of Louisville, Louisville, KY 40202 USA.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Wasser
authors.affiliation: Department of Epidemiology and Population Health, University of Louisville, Louisville, KY 40202 USA.
authors.forename: Richard N
authors.initials: RN
authors.lastname: Baumgartner
authors.affiliation: Division of Maternal-Fetal Medicine, University of Louisville, Louisville, KY 40202 USA.
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: King
authors.affiliation: Division of Endocrinology, Metabolism and Diabetes, University of Louisville, ACB-A3G11, 550 Jackson Street, Louisville, KY 40202 USA.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Winters
keywords: Maternal smoking; Newborn; Obesity; Sex hormone binding globulin