Maternal laboratory stress influences fetal neurobehavior: Cortisol does not provide all answers

Objective. Maternal stress can have an impact on pregnancy. However, effects on fetal neurobehavior are not well understood. In this study, the effect of laboratory stress on maternal psychoneuroendocrinological response and on fetal neurobehavior was studied. Serum cortisol as a potential underlying mechanism was measured. Methods. Twenty-seven women made a single 1.5-h visit in their third trimester. The laboratory stressor involved an arithmetic task. Associations between maternal laboratory stress response and fetal neurobehavior were analyzed by studying 19 maternal-fetal dyads with high signal quality cardiotocograms. Results. Stress exposure changed participants stress perception (p < 0.0001). However, only half of the participants (responders) had an HPA-axis response. Fetuses responded to the stress exposure depending on their mothers' stress response: (i) there was a fetal heart rate (FHR) group effect at the level of trend (p = 0.06). Fetuses of responders had higher HR levels 20 min after the exposure (p = 0.043), (ii) there were interaction (p = 0.026) and group effects at the level of trend (p = 0.078) found for FHR short-term variation (STV). Fetuses of responders had lower FHR STV 20 min after stress exposure (p = 0.007). Cortisol as a potential underlying mechanism only seemed to be associated with short- and long-term variation of FHR. Conclusions. An activation of the maternal stress-system could result in a child being born having a history of responding to maternal stress.