Maternal weight gain predicts sex hormone binding globulin (SHBG) levels in the newborn

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 596-630-Pediatric Endocrinology
Clinical
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-616
Swapna Dharashivkar*, Lawrence Wasser, Jeffrey King, Richard Baumgartner, Dushan T Ghooray and Stephen J Winters*
University of Louisville, Louisville, KY
Maternal obesity and weight gain during pregnancy are associated with large for gestational age babies and childhood obesity, and are thought to influence lifelong health through genetic factors, modifications by the intrauterine environment, and gestational programming of genes that control energy metabolism. Sex hormone binding globulin (SHBG), a glycoprotein produced by hepatocytes that is negatively associated with obesity, is a marker for the development of the metabolic syndrome (MetS) and T2DM. SHBG is also produced by the placenta, and is found in umbilical cord blood. As in children and adults, there is considerable between-individual variation in SHBG levels in cord blood, and some data suggest that low SHBG in cord blood is associated with maternal obesity and insulin resistance. In this study, we measured SHBG levels in cord blood and in a heel-stick blood sample on postnatal day 2 in 19 healthy singleton babies (10M,9F) born full term following an uncomplicated pregnancy.  Maternal pre-pregnancy weight and weight gain during pregnancy were assessed from chart review or by recall. The neonates anthropometric data were obtained at birth, and subscapular, flank and triceps skin fold thickness were measured using a Harpenden caliper on days 1-2.  Mean (±SEM) SHBG levels in cord blood were 43.6±3.9 (20.1-67.5) and in heel stick blood were 30±2.3 (15.2-55.2) nmol/L. Cord and heel stick SHBG levels were strongly positively correlated (r=0.66; p<0.01), and mean heel stick levels were 31% lower than in cord blood. There was no sex difference in either cord (44.9±6.7 vs 42.1±4.3 nmol/L) or heel stick (29.5±2.4 vs 30.5±4.2) SHBG (MvsF). Pregnancy weight gain was negatively associated with heel stick SHBG (r= -0.50; p<0.05) and cord blood SHBG (r= -0.35), but maternal pre-pregnancy weight was unrelated to SHBG in newborns (r=0.136 and r=0.09).  There was a negative association between placental weight and SHBG levels in heel stick blood (r= -0.33) but less so in cord blood (r= -0.18).  Increasing birth weight was inversely related to SHBG in heel stick (r= -0.26) and cord blood (r= -0.38), and subscapular fat fold (r= -0.22), triceps skin fold (r = -0.26) and flank skin fold thickness (r= -0.19) were negatively associated with heel stick SHBG but without statistical significance. We conclude that maternal weight gain but not maternal pre-pregnancy weight appears to predict the level of SHBG in the newborn. Higher birth weight babies with greater subscapular, triceps and flank skin fold thickness have lower SHBG levels. Higher SHBG in cord blood than in heel stick blood may represent the contribution of placental SHBG. These data suggest that maternal weight gain may lead to the early life programming of the metabolic processes that link low SHBG to the MetS and T2DM, and we propose heel-stick SHBG as a novel biomarker to identify babies at risk for obesity and its consequences in adult life.

Nothing to Disclose: SD, LW, JK, RB, DTG, SJW

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: x