Peripartum prolactin and cortisol level changes. A prospective pilot study.

Although the role of prolactin and cortisol in the human lactation process seems to be undisputed, the changes in postpartum serum concentrations in mothers make data interpretation difficult. To determine the factors that possibly influence these hormones, we examined a group of patients who were admitted to the Gynecology-Obstetrics Clinical Hospital in Poznan for labor induction and/or in the active phase of the first labor period. The serum levels of cortisol and prolactin were assessed in these full-term pregnant women during admission to labor, in the third stage of labor, and on the second day postpartum. The prolactin and cortisol levels were also measured in the umbilical cord for the assessment of newborn babies. The results showed a significant relationship between maternal age and the level of prolactin measured before childbirth and fluctuations in cortisol level with respect to labor duration. In addition, we observed a strong correlation between the level of prolactin assessed before childbirth and the pH and base excess of the umbilical cord artery. Most importantly, a correlation was noted between breastfeeding within two hours after the labor and the level of cortisol measured after childbirth, which is worth mentioning to emphasize the significance of early maternal-neonatal skin-to-skin contact.