Background: This study assessed the stability of maternal anxiety and concordance between State-Trait Anxiety Inventory (STAI) scores in the immediate postpartum period to 8 weeks postpartum.
Methods: A population-based sample of 522 mothers completed the STAI at 1, 4, and 8 weeks postpartum. Sensitivity, specificity, and predictive power of the 1-week STAI in relation to identifying mothers with elevated STAI scores at 4 and 8 weeks was determined. Predictive power of the STAI was further assessed using odds ratios and receiver operator characteristic (ROC) curves.
Results: At 1 week postpartum, 22.6% of mothers scored >40 on the STAI, decreasing to 17.2% at 4 weeks and 14.8% at 8 weeks. Using the cut-off score of >40, the 1-week STAI accurately classified 84.0% mothers at 4 weeks and 83.6% at 8 weeks with or without anxiety symptomatology. The 1-week STAI was significantly correlated to the 4-week (r=0.68, p<0.001) and 8-week (r=0.64, p<0.001) STAI. Mothers with a 1-week STAI score >40 were 15.2 times more likely at 4 weeks (95% CI=8.9-26.1) and 14.0 times more likely at 8 weeks (95% CI=7.9-24.8) to exhibit postpartum anxiety symptomatology.
Limitations: Psychiatric interviews were not completed in collaboration with the STAI and specific types of anxiety disorders were not identified.
Conclusions: A cut-off score of >40 on the STAI administered early in the postpartum period is recommended in a 2-phase identification program in order to not miss mothers with postpartum anxiety.
Keywords: Postpartum anxiety; Predictive validity; Screening; Sensitivity and specificity; State-Trait Anxiety Inventory.
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