When More Is Not Always Better: Linear and Nonlinear Predictors of Maternal Wellbeing During Pregnancy.

Maternal wellbeing during pregnancy is an important component of maternal mental health and has implications for both maternal and child outcomes. Although psychological resources such as self-control and social support are generally assumed to promote wellbeing, maternal wellbeing may also be influenced by psychological vulnerabilities, including perceived stress and ADHD (Attention Deficit Hyperactivity Disorder) symptoms. Recent theoretical perspectives further suggest that some beneficial characteristics may exhibit diminishing returns at higher levels. This study examined linear and nonlinear associations among perceived stress, ADHD symptoms, self-control, perceived social support, and maternal wellbeing during the second trimester of pregnancy. A sample of 149 first-time pregnant women from Romania completed measures of maternal wellbeing, perceived stress, ADHD symptoms, self-control, and perceived support from partners, family members, and friends. Hierarchical regression analyses were conducted, including quadratic terms derived from the Too-Much-of-a-Good-Thing framework. Perceived stress emerged as the strongest predictor of lower maternal wellbeing, whereas family support was positively associated with wellbeing. ADHD symptoms were negatively associated with wellbeing at the bivariate level but did not uniquely predict wellbeing after controlling for the remaining study variables. Most importantly, self-control demonstrated a significant nonlinear association characterized by diminishing returns, such that increases in self-control were associated with progressively smaller improvements in wellbeing at higher levels. No comparable nonlinear effects were observed for perceived stress or social support. Overall, the findings suggest that maternal wellbeing is shaped by both psychological vulnerabilities and psychological resources, and that the benefits of some psychological strengths may not increase uniformly across their entire range.