Couples’ relationship affects mothers’ and fathers’ anxiety and depression trajectories over the transition to parenthood

•Couple negative interaction moderated mothers’ and fathers’ depression symptoms from 3- to 30-months postpartum.•Mothers and fathers with high negative interaction scores experienced a steeper increase in depression symptoms from 3- to 30-months postpartum, than those with low negative interaction scores.•Fathers with low positive interaction scores experienced an increase in anxiety symptoms from 3- to 30-months postpartum, whereas those with high positive interaction did not experience changes in anxiety symptoms. The association between the couple relationship and the mothers’ and fathers’ psychological adjustment to the transition to parenthood has been examined in the literature. However, the direction of effects between these variables has not been extensively explored. This study aimed to assess the direction of effects between mothers’ and fathers’ positive and negative interactions and anxiety and depression symptoms trajectories over the transition to parenthood. A sample of 129 couples (N = 258) completed self-report measures of positive and negative interactions, anxiety and depression symptoms at each trimester of pregnancy, at childbirth, and at 3- and 30-months postpartum. Dyadic growth curve models were performed using multilevel modeling. Whereas anxiety and depression showed no moderation effect on positive and negative interactions over time, negative interaction moderated depression from 3- to 30-months postpartum. Mothers and fathers with high negative interaction scores experienced a steeper increase in depression from 3- to 30-months postpartum. Additionally, gender moderated the effect of positive interaction on anxiety from 3- to 30-months postpartum. Fathers with low positive interaction scores experienced an increase in anxiety, whereas fathers with high positive interaction scores and mothers with high or low positive interaction scores did not experience changes in anxiety from 3- to 30-months postpartum. Despite the longitudinal aspect of the models, a possible causal relationship need to be taken with caution. Our results suggest that mothers’ and fathers’ positive and negative interactions affect their anxiety and depression symptoms trajectories: negative interaction raises mothers’ and fathers’ depression symptoms and positive interaction prevents the increase of fathers’ anxiety symptoms over the postpartum period.