UCLA

Objective

Previous research has shown that a woman's anxiety about her pregnancy predicts gestational length. Placental corticotrophin-releasing hormone (CRH) is a stress-responsive peptide proposed as a mechanism. We examined placental CRH as a physiological mediator of the association between pregnancy anxiety and gestational length in Latina and non-Latina White women to replicate evidence of associations between pregnancy anxiety, placental CRH and gestational length; to test whether placental CRH levels or changes mediate effects of pregnancy anxiety on gestational length; to examine ethnic differences in pregnancy anxiety, placental CRH, and gestational length; and to explore whether the effects of pregnancy anxiety on gestational length as mediated by placental CRH vary by ethnicity.

Methods

In a prospective study of 337 pregnant Latina and non-Latina White women, participants completed in-person interviews that included a 10-item measure of pregnancy anxiety and provided blood samples assayed using radioimmunoassay at three timepoints (19, 25, and 31 weeks gestation).

Results

Pregnancy anxiety at 19 and 31 weeks and levels of placental CRH at 31 weeks predicted gestational length. Tests of indirect effects were consistent with mediation such that both pregnancy anxiety at 19 weeks and increases from 19 to 31 weeks predicted placental CRH at 31 weeks, which in turn predicted gestational length. Tests of moderated mediation by ethnicity showed that the mediated effect of placental CRH at 31 weeks was significant for Latinas only.

Conclusions

These findings add to growing evidence of the involvement of pregnancy anxiety in the timing of birth, address mechanisms, and suggest possible ethnic differences.