Serial Diurnal Salivary Cortisol Profiles in 667 Pregnant Women—Association With Cardiometabolic Complications

TL;DR

This study examines how cortisol levels change during pregnancy and how they relate to maternal health conditions like obesity, high blood pressure, and gestational diabetes.

Contribution

The study provides new insights into how maternal cortisol profiles change during pregnancy and their potential link to BMI.

Findings

Cortisol awakening response (CAR) declined in most women during pregnancy.

Higher BMI was associated with less decline in CAR and less attenuation in diurnal slope.

Hypertensive pregnancy disorders and GDM were not significantly linked to cortisol profiles.

Abstract

Maternal obesity, hypertensive pregnancy disorders, and gestational diabetes (GDM) are linked to an increased risk of negative offspring health outcomes. This association may be mediated by maternal hypothalamic-pituitary-adrenal axis (HPA axis) activity, resulting in elevated maternal cortisol levels and fetal exposure, but evidence remains scarce.

We (1) examined maternal diurnal cortisol profiles longitudinally across gestation, and (2) explored associations with maternal cardiometabolic complications.

Women in the InTraUterine sampling in early pregnancy (ITU) study (n = 667) provided 7 salivary cortisol samples from awakening to bedtime up to 3 times during pregnancy (median gestational week 19.3, 25.7, and 38.1; n = 9356 samples). Changes in cortisol awakening response (CAR) and diurnal slope (indicative of HPA axis activity) and their associations with maternal body mass index (BMI), hypertensive pregnancy disorders and GDM were examined using linear mixed models.

The CAR declined in 60% to 67% of women, and the diurnal slope attenuated from early to late pregnancy (b = 0.006; P = .001). Higher BMI was associated with less decline in CAR (b = 0.031; P = .0004) and less attenuation in diurnal slope from early to late pregnancy (b = −0.001; P = .006). Hypertensive pregnancy disorders and GDM were not significantly associated with diurnal cortisol profiles.

The attenuation in CAR and diurnal slope support HPA axis hyporesponsivity during pregnancy. Less attenuation of both markers in women with a higher BMI may indicate reduced adaption of the HPA axis to pregnancy, presenting a mechanistic link to offspring health outcomes.

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