Affective symptoms in pregnancy are associated with the vaginal microbiome

Composition of the vaginal microbiome in pregnancy is associated with adverse maternal, obstetric, and child health outcomes. Therefore, identifying sources of individual differences in the vaginal microbiome is of considerable clinical and public health interest. The current study tested the hypothesis that vaginal microbiome composition during pregnancy is associated with an individual's experience of affective symptoms and stress exposure.

Data were based on a prospective longitudinal study of a medically healthy community sample of 275 mother-infant pairs. Affective symptoms and stress exposure and select measures of associated biomarkers (diurnal salivary cortisol, serum measures of sex hormones) were collected at each trimester; self-report, clinical, and medical records were used to collect detailed data on socio-demographic factors and health behavior, including diet and sleep. Vaginal microbiome samples were collected in the third trimester (34-40 weeks) and characterized by 16S rRNA sequencing. Identified taxa were clustered into three community clusters (CC1-3) based on dissimilarity of vaginal microbiota composition.

Results indicate that depressive symptoms during pregnancy were reliably associated with individual taxa and CC3 in the third trimester. Prediction of functional potential from 16S taxonomy revealed a differential abundance of metabolic pathways in CC1-3 and individual taxa, including biosynthetic pathways for serotonin and dopamine. We did not find robust evidence linking symptom- and stress-related biomarkers and CCs.

Our results provide further evidence of how prenatal psychological distress during pregnancy alters the maternal-fetal microbiome ecosystem that may be important for understanding maternal and child health outcomes.