Associations of maternal psychological factors with umbilical and uterine blood flow.

OBJECTIVE Alteration to blood flow in the maternal-foetal compartment has been proposed as a mechanism underlying maternal psychological effects on pregnancy outcomes. This study characterised the progression of umbilical and uterine blood flow resistance in healthy pregnancies and evaluated concurrent and longitudinal associations with maternal anxiety and other psychological factors. METHODS The study assessed participants (n=107) at five visits spanning 24-38 weeks gestation. The resistance index (RI) in the uterine and umbilical arteries was measured with Doppler ultrasound. Maternal psychological function was assessed using validated, self-report instruments. RESULTS Hierarchical linear modelling revealed that uterine and umbilical RI decreased during the second half of gestation, and that uterine RI was lower in nulliparous women. Few concurrent associations emerged between psychological factors and RI. Longitudinal analyses determined that psychological well-being was associated with decreased left uterine artery RI, and psychological distress was associated with lower right artery RI. CONCLUSIONS Although uterine artery resistance was modestly associated with the maternal psychological milieu during gestation, our findings do not indicate an association between increased maternal distress and decreased RI. Thus, this study fails to affirm a key component of the hypothesised relation of maternal stress to foetal outcomes via vasoconstriction.