BOSTON — Maternal cortisol levels during pregnancy are highly correlated with newborn cortisol levels in the first days of life, a study has shown. Additionally, both prenatal anxiety and postpartum depression independently predict newborn cortisol levels, according to Raquel Costa, a doctoral candidate at the University of Minho in Braga, Portugal.
These findings from a prospective investigation of 56 mother-child pairs support the hypothesis that a woman's emotional state both during pregnancy and after childbirth can have a significant effect on newborn physiology, Ms. Costa said in a poster presentation at a meeting of the Society for Research in Child Development.
All of the women in the current study were enrolled during their third trimester of pregnancy, and none had multiple gestations. Upon enrollment through 48 hours after childbirth, each woman provided 24 urine samples to measure cortisol levels, as well as blood samples to measure oxytocin levels. For assessment of depression and anxiety at both time points, each woman completed the 10-item Edinburgh Postnatal Depression Scale (EPDS) and the State-Trait Anxiety Inventory (STAI). Newborn cortisol levels were measured via urine sample within 2 days of birth.
Approximately 30% of the mothers screened positive for depression during pregnancy, and 17% screened positive after childbirth, Ms. Costa said. With respect to anxiety, positive screens were observed in 29% of the women prior to giving birth and 20% after childbirth, she said.
Measurement of maternal cortisol showed that approximately 53% of the women had levels higher than the normative range of 20–90 mcg/24 hours during pregnancy, and 17% had levels higher than the normative range after childbirth, Ms. Costa reported.
Regarding oxytocin measurements, prior to childbirth 52% of the women had levels higher than the group's mean. Following childbirth, 45% of the mothers had oxytocin levels higher than the group's postpartum mean.
In a t test for independent samples to analyze differences in newborns' cortisol levels according to mothers' depressive mood, anxiety, oxytocin, and cortisol levels before and after childbirth, “there were no significant differences in newborn cortisol levels according to mother's psychopathology or hormone levels,” Ms. Costa stated.
However, linear regression analysis on the neonatal cortisol levels with the maternal depressive mood, anxiety, oxytocin, and cortisol levels both during pregnancy and post partum “suggested that maternal anxiety during pregnancy and depression after childbirth were predictive of neonatal cortisol levels,” said Ms. Costa. Neither maternal cortisol nor oxytocin levels were predictive of newborn cortisol levels in the regression analyses, she noted.
Together with the results of earlier studies linking elevated prenatal cortisol levels in mothers to short gestation and low birth weight in newborns, and those associating prenatal stress with behavioral problems and motor/cognitive deficits in newborns, the findings of the current study highlight the importance of assessing maternal emotional status and stress hormone levels during pregnancy, and implementing early intervention strategies when warranted, Ms. Costa said.