Before pregnancy trauma primes oxytocin receptor expression in placenta during superstorm sandy

Given the role of sympathetic nervous system and hypothalamic-pituitary-adrenal (HPA) axis in trauma transmission and oxytocin's stress buffering effects, this study examined whether placental oxytocin receptor (OXTR) gene expression differs by maternal trauma exposure status.

A sample (N = 152) was drawn from a longitudinal birth cohort. OXTR was quantified using nCounter platform as expressed or unexpressed. Maternal trauma exposure was assessed via validated questionnaire and categorized into four groups: before pregnancy trauma, Superstorm Sandy exposure during pregnancy, both, or neither (reference). Logistic regression and synergy index (SI) were calculated to examine individual and additive interaction effects.

In the proportion of samples with detectable OXTR, neither individual exposure significantly altered placental OXTR expression. However, both traumas exposure group had an over a 6-fold increase (OR = 6.13, p = .01) compared to the reference. The SI was 2.17 suggesting that the combined effect of both traumas exceeded the sum of their individual effects on placental OXTR expression.

Given oxytocin linked placental adaptations to cope with consequences of stress, this greater-than-additive modification, as evidenced by the synergy index, suggests trauma exposure before pregnancy fundamentally changes how the placenta responds to disaster exposure during pregnancy in anticipation of harsh external conditions.