Introduction: A large body of research has found that chronic high levels of irritability are associated with reduced quality of life, poor sleep quality and interpersonal conflict. Similarly, anger is associated with an increased risk for cardiovascular disease and poor mental health. A limited body of research suggests that pregnancy is associated with greater variability in mood and potentially a higher prevalence of anger and irritability. The aim of the current study was to investigate maternal trajectories of irritability and anger and to identify specific factors that differentiate women’s trajectory membership.
Methods: 142 pregnant women were recruited from a low-risk maternity clinic in Calgary, AB. Participants completed online surveys at four time points: T1 (< 20 weeks gestational age [GA]), T2 (20 – 29 weeks GA), T3 (30 – 39 weeks GA), and postpartum at T4 (2 months postpartum). A group-based semiparametric mixture model revealed unique trajectories and multinomial logistic regression identified baseline predictors.
Results: Irritability trajectories were defined by low-stable irritability (51%), moderate-stable irritability (26.1%), high-stable irritability (15.6%) and high-decreasing irritability (7.3%). For anger symptoms, trajectories identified included, low-stable anger (52.4%), moderate-stable anger (27.5%), high-stable anger (12.7%) and high-decreasing anger (7.4%). Higher odds of membership in the high-stable irritability and anger trajectories were associated with higher baseline anxiety (p < .001) and insomnia severity (p < .001) scores, but not with interpersonal support (social support), household income or level of education, compared to the low-stable trajectory. Depression was a significant baseline predictor of anger trajectory membership (p = .043) but not irritability (p = 0.41).
Conclusion: A subgroup of women reported a significant decline in irritability and anger from early to late pregnancy and another reported high-stable irritability and anger through pregnancy and postpartum. Results provide novel evidence that these subgroups can be distinguished based on anxiety and insomnia symptoms in early pregnancy.