Depression and anxiety occur frequently in pregnancy and may have unfavourable consequences for mother and child. Therefore, adequate symptom measurement seems important. Commonly used instruments are the Center for Epidemiologic Studies Depression Scale (CES-D), the Edinburgh Postpartum Depression Scale (EPDS), and the Hospital Anxiety and Depression Scale, anxiety subscale (HADS-A). We compared the (1) structural and (2) longitudinal validity of these instruments. The data originated from a study on the effectiveness of an Internet intervention for pregnant women with affective symptoms. (1) A confirmatory factor analysis was used to estimate the construct validity. The theoretical factorial structure that was defined in earlier studies of the CES-D and the EPDS, but not the HADS-A, could be sufficiently replicated with acceptable CFI and RMSEA values. (2) Since there were two measurements in time, the hypotheses concerning plausible directions of the change scores of subscales that were (un)related to each other could be formulated and tested. In this way, longitudinal validity in the form of responsiveness was estimated. Ten of sixteen hypotheses were confirmed, corroborating the longitudinal validity of all constructs, except anhedonia, probably due to inconsistent conceptualization. The HADS-A seems less suitable to screen for anxiety in pregnancy. Anhedonia needs better conceptualisation to assess the change of symptoms over time with the CES-D and the EPDS.
Keywords: perinatal anxiety; perinatal depression; pregnancy; questionnaires; responsiveness; screening; structural validity.