Cortisol in early pregnancy: Impact on pregnancy outcomes

Maternal cortisol may influence pregnancy outcomes, including preterm birth (PTB), though evidence remains inconsistent.

To investigate the association between early pregnancy cortisol, perceived stress, and adverse pregnancy outcomes.

A prospective cohort study.

Of 432 multigravida women categorized by prior PTB history (high-risk vs. low-risk), 202 were analyzed who were at 11-13 gestational weeks with standardized afternoon saliva collection (14:00-18:00). Saliva samples and stress questionnaires were collected. Pregnancy outcomes were compared between women with high and low salivary cortisol levels. Mean salivary cortisol levels were compared between high- and low-risk groups, as well as between women with and without selected pregnancy complications.

High-risk women had significantly higher mean cortisol (0.193 μg/dL vs. 0.144 μg/dL, p-value = 0.004). and 3.29-fold higher odds of elevated cortisol (aOR = 3.29, 95% CI: 1.55-6.96, p-value = 0.002). PTB rates were 21.4% in high-risk vs. 3.5%in low-risk women (p-value<0.001), high cortisol levels were not significantly predictive of current PTB in multivariable models (p-value = 0.099), despite high odds ratios (3.14). However, high cortisol levels were significantly associated with gestational hypertension (GHTN) (100% vs. 23.5%, p-value = 0.014) and fetal malformations (62.5% vs. 23.1%, p-value = 0.024). No association was found between perceived stress and cortisol levels.

Early pregnancy cortisol is significantly elevated in women with a history of PTB, reflecting HPA axis dysregulation. While not a reliable predictor for recurrent PTB at 11-13 gestational weeks, high cortisol is associated with GHTN and malformations, suggesting it may serve as a marker for specific adverse outcomes.