Induction of labor, and physiological and psychological stress responses as expressed by salivary cortisol: a prospective study

Purpose: To describe patterns of physiological and psychological stress during induced labor and their correlation to obstetrical and neonatal outcomes. Methods: This prospective, observational study included 167 women, with low-risk, singleton pregnancies, who delivered at term, at a tertiary academic center from 2015 through 2018. Among them, 72 (43%) underwent induction and 95 (57%) had spontaneous labor onset. Physiological stress was evaluated by salivary cortisol measurements and emotional stress by questionnaires (visual analogue stress scale 0–10) during latent phase, active phase and full dilation stages of labor, as well as 2 min and 2 h postpartum. Cord blood cortisol and pH were obtained. Stress patterns were compared between parturients who did or did not undergo induction. Modes of delivery, labor and delivery complications, and early neonatal outcomes were compared. Mothers completed the Hospital Anxiety and Depression Scale. Results: Induced women had lower cortisol concentrations during the latent phase compared to spontaneous onset of labor (p = 0.003), with no differences during active (p = 0.237), full dilation (0.668), 2 min and 2 h after delivery (p = 0.666). Stress scale and Hospital Anxiety and Depression Scale scores were similar between groups. Cord cortisol (p = 0.294), 1-min Apgar score ≤ 7 (p = 0.502) and 5-min Apgar score ≤ 7 (p = 0.37) were similar. All had cord pH > 7. Conclusions: Induction does not increase stress during labor. Moreover, it might have a positive effect on reducing cortisol during the latent phase. These findings might reassure women who are concerned about induction of labor.