Fetal motor activity and maternal cortisol

Abstract

The contemporaneous association between maternal salivary cortisol and fetal motor activity was examined at 32 and 36 weeks gestation. Higher maternal cortisol was positively associated with the amplitude of fetal motor activity at 32 weeks, r(48) = .39, p < .01, and 36 weeks, r(77) = .27, p < .05, and the amount of time fetuses spent moving at 32 weeks during the 50 min observation period, r(48) = 33, p < .05. Observation of periods of unusually intense fetal motor activity were more common in fetuses of women with higher cortisol, Mann-Whitney U = 58.5. There were no sex differences in fetal motor activity, but the associations between maternal cortisol and fetal motor amplitude and overall movement were significantly stronger for male than female fetuses.

Figure 1

Schematic description of 32 and 36 week protocols. Note that the initial saliva sample was collected after other protocol activities such as informed consent (week 32) and ultrasound. The elapsed time between saliva collections is longer than the fetal monitoring period because it includes activities such as application of monitoring equipment and preparation for sample collection.

Figure 2

Eight-minute sample of digitized fetal actograph data.