The development and initial validation of a screening scale for antenatal anxiety

Abstract

Background: Anxiety during pregnancy is a strong predictor of postnatal depression and can negatively impact on a range of child developmental outcomes. Recent reviews highlight the lack of anxiety measures with robust psychometric properties for screening use in pregnancy. Aim: This research aimed to develop a brief self-report scale specifically constructed to identify problematic anxiety symptoms in pregnant women, and conduct preliminary psychometric testing of the scale. Method: The development and psychometric validation of the SAAS (Stirling Antenatal Anxiety Scale) was informed by five studies. A systematic review of the psychometric literature and interviews with women with experience of problematic anxiety symptoms in pregnancy both contributed to the generation of an initial item pool for the assessment of the target construct. This was subsequently refined and reduced, using a Delphi technique involving key informants (i.e. expert opinion and target population). The screening accuracy of the final, 10-item version of the scale was subsequently tested against a diagnostic interview, and compared to the NICE-recommended screening scales for antenatal anxiety (GAD-2/7). The internal consistency, factor structure and construct validity of the SAAS were also assessed. Results: 174 women completed the SAAS, GAD-2/7 and Edinburgh Postnatal Depression Scale (EPDS). The SAAS was found to have excellent sensitivity (91%) and very good specificity (85%) at its optimal cut-off score of ≥ 8. It also showed a superior screening performance when compared to both the GAD-2 and the GAD-7 at their NICE-recommended cut-off scores. Its internal consistency was close to excellent (α = 0.88), and the scale exhibited a single-factor structure. The SAAS was also considered highly acceptable to pregnant women (mean score = 9.48; range 1-10). Conclusion: The SAAS shows promise as a brief, acceptable and effective screening tool for antenatal anxiety, which may improve identification and aid appropriate targeting of resources and care.