While postpartum depression is common among new mothers, our ability to reliably detect this illness remains poor. Recent studies have indicated that most obstetricians report that they screen for postpartum psychiatric problems at routine follow-up visits but typically do not use standardized instruments to assess for postpartum depression. Unfortunately, studies which have measured the success of routine screening suggest that without the use of standardized screening tools like the Edinburgh Postnatal Depression Scale, many women with postpartum depression are not identified.
What is the best screening tool?
The Edinburgh Postnatal Depression Scale (EPDS) is the screening instrument most commonly used to identify women with postpartum mood disorders. This is a 10-item questionnaire which has been validated in many different populations and is available in almost every language. On this scale, a score of 10 or greater or an affirmative answer on question 10 (presence of suicidal thoughts) is suggestive of postpartum depression. (Setting the cut-off score of 12 improves the specificity of the EPDS for identifying major depression; however, the sensitivity falls off significantly, making it less useful for screening.) Most importantly it should be emphasized that an elevated score on the EPDS does not necessarily confirm the diagnosis of postpartum depression; this requires a more thorough diagnostic evaluation.
A recent study indicated that the EPDS may be further abbreviated to a three question version which can be used to screen for postpartum depression. Given the prevalence of anxiety symptoms among women with postpartum depression, the authors chose a screening tool using the 3 items which comprise the anxiety subscale of the EPDS:
1. I have blamed myself unnecessarily when things went wrong
2. I have been anxious or worried for no good reason
3. I have felt scared or panicky for no very good reason
The EPDS-3 exhibited a sensitivity of 95% and a negative predictive value or 98%; interestingly, this study indicated that the short version of the EPDS had greater sensitivity and thus may be a better screening tool than the full version of the EPDS.
Other screening tools have been used to screen for postpartum depression. The Postpartum Depression Screening Scale (PDSS) was created specifically for postpartum women and is a 35-item, self-report questionnaire which about 5 to 10 minutes to complete.
Other tools, like the Hamilton Depression Rating Scale and the Beck Depression Inventory, have not been validated in pregnant and postpartum populations.
When is the best time to screen?
Mood fluctuations are extremely common during the first postpartum week, with approximately 60%-85% of women reporting mild to moderate mood symptoms, or “the blues”. While this may complicate screening, studies which have used the EPDS to screen for depressive symptoms within the first postpartum week suggest that the EPDS may be used to predict which women will go on to have postpartum depression. In this study, women who scored 9 or greater on the EPDS were about 30 times as likely to have postpartum depression at week 4 than women with lower EPDS scores. Similar results were observed when the EPDS was administered at 2-3 days postpartum.
Ruta Nonacs, MD PhD
Kabir K, Sheeder J, Kelly LS. Identifying postpartum depression: Are 3 questions as good as 10? Pediatrics 2008, 122(3):e696-e702