The literature has mainly focused on the impact of the negative aspects of the couple's relationship on the toddler's internalizing and externalizing problems. This study explored the impact of the positive and negative dimensions of the couple's relationship during the transition to parenthood on toddlers' psychological adjustment, considering the concurrent impact of the couple's relationship at 30 months postpartum. The sample comprised 115 mothers and fathers (N = 230) recruited during the 1st trimester of pregnancy. The mothers and fathers individually completed a measure of the couple's relationship (Relationship Questionnaire) during the first trimester of pregnancy, at 3 and 30 months postpartum, and the Child Behavior Checklist 1.5-5 at 30 months postpartum. Multiple linear regressions, cluster analyses, and univariate and multivariate analyses of variance were conducted. The positive dimension at the 1st trimester of pregnancy and the negative dimension of the couple's relationship at 3 months postpartum were the strongest predictors of the toddler's internalizing problems, while the negative dimension at 3 months postpartum and the positive dimension of the couple's relationship at 30 months postpartum were the strongest predictors of the toddler's externalizing problems. Two patterns of the couple's relationship (adjusted vs. non-adjusted) during the transition to parenthood were identified. Higher levels of internalizing and externalizing problems were found in toddlers from couples with a non-adjusted couple's relationship. Findings suggested the impact of both positive and negative dimensions of the couple's relationship during the transition to parenthood on the toddler's emotional and behavioral problems. Promoting the couple's relationship adjustment during the transition to parenthood can help to prevent toddlers' emotional and behavioral problems.
Keywords: couple’s relationship; emotional and behavioral problems; internalizing and externalizing problems; toddlers.