Maternal hair cortisol concentrations and its association with increased insulin resistance in mid-pregnancy.

PURPOSE: Stress and elevated maternal glycemia have negative effects on pregnancy. We evaluated the association of hair cortisol concentrations (HCC), a marker of chronic stress, with insulin resistance and gestational diabetes (GDM).

METHODS: 527 women from Lima, Peru, provided a hair sample in the second trimester of their pregnancy to measure HCC using liquid chromatography-tandem mass spectrometry. Each 6 cm of hair captured HCC in early (T1=1-12 weeks) and mid-pregnancy (T2=13-24 weeks). Routine screening was implemented to diagnose GDM in mid-pregnancy (IADPSG criteria). Multivariable linear and logistic regression models mutually adjusted for putative risk factors, including maternal sociodemographic factors, diabetes history, and hair characteristics, were used to estimate the association of HCC with GDM and other glycemic traits.

RESULTS: GDM was diagnosed in 122 (23%) women. Mean HCC across pregnancy was T1=3.7 (± 3.4) pg/mg and T2=4.8 (± 3.4) pg/mg. HCC was associated with increased log-transformed units of fasting insulin [T1=0.15 (0.03,0.27), T2=0.17 (0.04,0.30)], HOMA-IR [T1=0.14 (0.01,0.26), T2=0.17 (0.03,0.30)], and HOMA-B [T1=0.20 (0.05,0.34), T2=0.20 (0.04,0.36)], but not with the odds of GDM [T1=0.95 (0.63,1.40), T2=1.11 (0.74,1.67)].

CONCLUSIONS: Elevated maternal HCC was associated with abnormal insulin homeostasis in pregnancy. Dysregulation of the hypothalamic-pituitary-adrenal axis, as reflected by high HCC, may also contribute to the insulin resistance syndrome in pregnancy.