RT Journal Article
SR Electronic
T1 PPO.21 Altered maternal hypothalamic-pituitary-adrenal axis activity in obese pregnancy: a potential mechanism underlying macrosomia and prolonged pregnancy
JF Archives of Disease in Childhood - Fetal and Neonatal Edition
JO Arch Dis Child Fetal Neonatal Ed
FD BMJ Publishing Group Ltd and Royal College of Paediatrics and Child Health
SP A157
OP A157
DO 10.1136/archdischild-2014-306576.461
VO 99
IS Suppl 1
A1 LI Stirrat
A1 JR O’Reilly
A1 SC Riley
A1 AF Howie
A1 R Smith
A1 BR Walker
A1 JE Norman
A1 RM Reynolds
YR 2014
UL http://fn.bmj.com/content/99/Suppl_1/A157.1.abstract
AB Background Increased hypothalamic-pituitary-adrenal (HPA) axis activity has been associated with low birthweight and preterm labour. Maternal obesity is associated with macrosomia (birthweight ≥4000 g) and prolonged pregnancy (≥41 weeks). We hypothesised altered HPA axis activity may underlie these pregnancy outcomes and aimed to characterise HPA axis hormones in obese pregnancy. Method Fasting serum cortisol was measured by radioimmunoassay at 16, 28 and 36 weeks in 286 obese (BMI 44.05 ± 3.98 kg/m2) and 137 lean (BMI 22.71 ± 1.66 kg/m2) pregnant women. In subsets (n = 20 obese, 20 lean) we measured corticosteroid-binding-globulin (CBG) and corticotrophin-releasing-hormone (CRH) by radioimmunoassay. Free cortisol was calculated using Coolen’s equation. Results Cortisol was significantly lower throughout pregnancy in obese (Table 1), and lower free cortisol at 16 weeks was associated with higher birthweight (r = -0.46, p < 0.05). Lower CRH at 28 weeks correlated with later gestation at delivery in obese (r = -0.56, p < 0.05) and remained significant as an independent predictor of gestation at delivery (beta = -3.19; p < 0.05). Lower CRH at 36 was associated with delivery ≥41 weeks (236.4 ± 172.7 pmol/L vs. 271.9 ± 233.8 pmol/L; p < 0.05) and with macrosomia (108.68 ± 31.7 pmol/L vs. 291.09 ± 216.32 pmol/L; p < 0.05). Conclusion Decreased HPA axis activity in obese pregnancy may underlie macrosomia and prolonged pregnancy.