Maternal and umbilical artery cortisol at birth: relationships with epidural analgesia and newborn alertness.

BACKGROUND: Newborn alertness soon after birth facilitates mother-infant interaction and may be related to umbilical cortisol levels. Yet, little is known about whether epidural analgesia influences umbilical cortisol at birth. AIM: The aims of this study were to explore relationships between exposure to epidural analgesia and maternal and umbilical cortisol; maternal and umbilical cortisol levels at birth; and umbilical cortisol and infant alertness after birth.
METHOD: Forty women were self-selected to unmedicated or epidural labors in this pilot study. Maternal saliva and infant umbilical artery (UA) plasma at birth were enzyme immunoassayed for cortisol. Infant alertness was assessed nearly 1 hr after birth.
RESULTS: Maternal cortisol was higher in the unmedicated versus epidural group (p = .003). Umbilical cortisol was not related to epidural analgesia exposure but was related to duration of labor (higher cortisol with longer labors; p = .026). Maternal cortisol level explained 55% of the variance in umbilical cortisol in the unmedicated group (p = .002), but there was no significant shared variance in the epidural sample (p = .776). There was a positive correlation (r(2) = .17, p = .008) between umbilical cortisol and infant alertness. Latina infants demonstrated a higher frequency of alertness than Black infants. In multivariate analysis, umbilical cortisol (p = .049) and race/ethnicity (p = .024) remained significant predictors of infant alertness.
CONCLUSIONS: Our findings indicate that higher umbilical cortisol is related to greater infant alertness soon after birth. While epidural analgesia did not directly relate to infant cortisol, other factors contributed to higher umbilical cortisol.