The primary aim of this study is to evaluate whether a CBT group designed to target IU (CBT-IU) in pregnant women with heightened levels of IU, prevents postpartum anxiety. The investigators hypothesize that women with clinically significant IU during pregnancy will exhibit both significant reductions in IU, as well as a decrease in anxiety symptoms postpartum, compared to a treatment as usual control group. The secondary aim of this study is to evaluate whether CBT-IU significantly improves and/or prevents depression symptoms, worry symptom severity, and difficulties with emotion regulation. The investigators hypothesize that CBT-IU will lead to significant improvements in symptom severity compared to the treatment as usual control group.

Anxiety disorders are a serious mental health concern, affecting as many as 15-24% of women during the perinatal period. Despite the high prevalence of anxiety during the perinatal period and its associated impact, fewer than 15% of women receive treatment often due to difficulties in timely and accurate symptom detection. Our group conducted a longitudinal study that investigated the psychosocial and biological risk factors of postpartum anxiety worsening in a sample of high-risk pregnant women with pre-existing anxiety and depressive disorders. In this study, intolerance of uncertainty (IU) was identified as the strongest predictor. IU is a cardinal trait of anxiety and has been implicated in predicting treatment response in non-perinatal populations. However, despite the relevance of IU in anxiety disorders, our study was the first to assess IU in the perinatal population. As improving symptom detection through identification of significant risk factors, such as IU, can aid in the development of preventative and treatment measures, our group recently validated the Intolerance of Uncertainty Scale (IUS) in a perinatal population for the detection of anxiety disorders. In this study of 198 perinatal women, the IUS demonstrated excellent internal consistency and an optimal clinical cut-off score of 64 or greater was established, yielding a sensitivity of 89%. The IUS also demonstrated very good positive (79%) and negative (80%) predictive values. These findings suggest that the IUS represents a clinically useful screening tool to be used as an aid for the early and accurate detection of anxiety disorders during the perinatal period. Cognitive Behavioural Therapy (CBT) is considered a first-line treatment for perinatal anxiety disorders and CBT programs targeting IU have revealed promising findings in non-perinatal populations.It is therefore imperative to investigate whether a treatment program specifically designed to target IU during pregnancy can prevent postpartum anxiety.

Inclusion Criteria:

• Pregnant women (up to 30 weeks pregnant to allow for completion of the CBT-IU protocol before child delivery)
• 18 years or older
• Baseline score of ≥64 on the IUS (Furtado et al., 2021)
• No psychotropic medication or, if taking medication, no change in dose or type for a minimum of 6 weeks prior to baseline
• No concurrent psychological treatment
• Fluent in English and able to consent for treatment
• Located in Ontario, Canada

Exclusion Criteria:

• A current diagnosed DSM-5 anxiety disorder, as assessed by the Mini International Neuropsychiatric Interview (version 7.0.2)
• Active suicidal ideation
• Current psychosis or substance use disorder
• For those enrolled on a stable dosage of a psychotropic medication, if a change in medication is required during the psychological therapy trial, the participant will continue with the therapy but will be excluded from the analysis.