Relationship Satisfaction Trajectories Across the Transition to Parenthood Among Low‐Risk Parents

One thing is a certainty during the transition to parenthood: adjustment. Adjustment, however, does not inevitably mean change for the worse, and not all parents necessarily experience the transition in the same way (Belsky & Hsieh, 1998; Belsky & Rovine, 1990). Indeed, the Vulnerability-Stress-Adaptation (VSA) model, as proposed by Karney and Bradbury (1995), suggests that adjustment to any stressful life event (like the transition to parenthood) will vary depending on the individual's or couple's enduring vulnerabilities, stressors, and adaptive processes. Despite the diversity with which new parents may adjust to the transition to parent-hood, differences in patterns of adjustment have been largely overlooked in past research. One specific outcome that has received particular attention in prior research is relationship sat-isfaction, with a plethora of studies indicating relationship satisfaction declines, on average, across the transition to parenthood (see Mitnick, Heyman, & Smith-Slep, 2009, for a review). Yet, because these studies tend to examine the average experience of new parents, the current literaturerevealslittleaboutdifferenttrajectories of change. Furthermore, no studies have exam-ined the vulnerability, stress, and adaptation risk factors that may distinguish membership in different trajectories of relationship satisfaction change. The current study fills the gap in the lit-eraturebyutilizingalow-risksampleof206new parents to identify distinct subgroups of change trajectories in relationship satisfaction. On the basis of the VSA model and interdependence theory (Rusbult & Arriaga, 1997), we examined prenatal actor and partner predictors of subgroup membership in relationship satisfaction change as well as whether individuals tend to experience similar patterns of change as their partner.RELATIONSHIP SATISFACTION ACROSS THE TRANSITION TO PARENTHOODA large body of research has established that new parents, on average, experience small to moderate declines in relationship satisfaction (e.g., Lawrence, Rothman, Cobb, Rothman, & Bradbury, 2008; Mitnick et al., 2009). Yet, as Mitnick and colleagues (2009) pointed out, there is considerable heterogeneity across different studies; although most studies have found that relationship satisfaction significantly declines across the transition to parenthood (e.g., Lawrence et al., 2008), others have not found such a decline (e.g., Wallace & Gotlib, 1990). Thus, the question remains: Why do only some studies find declines in relationship satisfaction across the transition to parenthood? We propose that different studies produce different results because of group differences in how parents experience the birth of their first child.Even though recent studies (e.g., Doss, Rhoades, Stanley, & Markman, 2009; Lawrence et al., 2008) have tended to find that relationship satisfaction declines, on average, across the transition to parenthood, an average trajectory may not adequately summarize relationship satisfaction change for all new parents. The VSA model suggests that relationship adjustment in response to any major stressful event will vary depending on the individual's or couple's enduring vulnerabilities, the stress of the event, and the individual's or couple's response to the event in order to adapt. Although existing studies have modeled individual variability around an average-change trajectory (Doss et al., 2009; Lawrence et al., 2008), fitting an average-change trajectory to an entire group of new parents may mask subgroups within the data, which could be distinct in nature (Nagin, 1999, 2005). For example, if a majority of new parents experience little change in relationship satisfaction while a smaller subgroup of parents experience large declines, the declining subgroup could drag the overall sample mean down. We call this the subgroup hypothesis, and it suggests two things: (a) that patterns of change for new parents are heterogeneous and (b) that a subgroup of parents who experience substantial declines will affect the mean change trajectory of the entire group. …