Assessing physical symptoms during the perinatal period: Reliability and validity of the Primary Health Questionnaire Somatic Symptom Subscale (PHQ-15)

Introduction: This study aimed to establish the reliability and validity of the Primary Health Questionnaire Somatic Symptom Severity Subscale (PHQ-15) for postpartum women. Methods: Women (N = 495) completed the PHQ-15 approximately six weeks postpartum during the baseline phase of a randomised controlled trial evaluating a writing intervention for postnatal health in England. Reliability was assessed using internal consistency statistics and convergent validity by comparing differences in self-reported physical health, health-related quality of life (QoL), and primary care usage by PHQ-15 symptom severity category. Results: Cronbach’s α for the PHQ-15 was 0.73 and item-total statistics met recommended guidelines. Validity analyses showed 6% of women reported severe symptoms, 17% medium, 50% low, and 27% minimal symptoms. Women with severe symptoms reported poorer overall physical health, poorer physical health-related QoL, and greater use of primary care. Women with severe symptoms also rated their baby’s health as worse and used primary care more for their baby. Discussion: This study suggests the PHQ-15 has the potential to be a useful and valid measure of physical symptoms in postpartum women in high-income countries