Partner relationship quality and IL-6:IL-10 trajectories from pregnancy to a year after-birth

Background: Inflammatory activity during pregnancy and the postpartum period shifts systematically due to pregnancy progression, delivery, and postpartum recovery. Factors that deregulate inflammatory activity increase the risk for adverse pregnancy outcomes and slower postpartum recovery. The IL-6:IL-10 or TNF-α:IL-10 ratio is potentially one way to capture peripheral inflammatory regulation; higher values indicate that anti-inflammatory IL-10 is less effective at regulating pro-inflammatory TNF-α or IL-6, skewing towards maladaptive pro-inflammatory profiles. Associations between partner relationship quality and IL-6:IL-10 or TNF-α:IL-10 trajectories during pregnancy and the postpartum period have not been assessed. The purpose of this study was to test whether partner relationship quality (support, conflict) is associated with attenuated IL-6, IL-10, TNF-α, TNF-α:IL-10 or IL-6:IL-10 trajectories from the third trimester to the postpartum period. Methods: A sample of 162 women from the Healthy Babies Before Birth study reported on partner relationship quality (support and conflict) using the Social Support Effectiveness Questionnaire during the third trimester. Plasma samples were collected in the third trimester and at 1-, 6- and 12-months postpartum, and assayed for TNF-α, IL-6 and IL-10. Associations between both indicators of relationship quality (support and conflict) and TNF-α, IL-6, IL-10, IL-6:IL-10, TNF-α:IL-10 trajectories were tested using multi-level modelling, controlling for sociodemographic, pregnancy and health variables. Results: Partner support interacted with time to predict IL-6:IL-10 trajectories, linear: b = -0.176, SE = 0.067, p =.010, quadratic: b = 0.012, SE = 0.005, p =.009. Lower partner support was associated with steeper increases in IL-6:IL-10 from the third trimester to 6 months postpartum, followed by steeper decreases in IL-6:IL-10 from 6 months postpartum to a year after birth. Partner conflict was not associated with IL-6:IL-10 levels at study entry, b = 0.233, SE = 0.219, p =.290, or over time, p's > 0.782. Neither indicator of partner relationship quality was associated with TNF-α, IL-6, IL-10, or TNF-α:IL-10 trajectories, p's > 0.205. Conclusion: Lower partner support may be associated with reduced moderation of IL-6 by IL-10 between pregnancy and a year postpartum, with possible consequences for maternal health and well-being.