Over the past few years, there has been a push to screen women for depression both during pregnancy and the postpartum period.   While there have been various initiatives mandating screening, there remain questions regarding the optimal timing of screening and the best screening tools to use.

The Edinburgh Postnatal Depression Scale (EPDS) is probably the tool most commonly used to identify women with postpartum depression.  It has also been validated for use in pregnant populations (Murray and Cox, 1990).

Typically the EPDS is used at a single time point to identify women with probable depression.  Many clinical services are now using the EPDS to routinely screen pregnant and postpartum women, and women with high EPDS scores are referred to a mental health provider for further evaluation.  There has, however, been some debate as to what cutoff score should be used in this setting.  To avoid missing cases, the American Academy of Pediatrics recommends using a score of > 10 to initiate a referral.  Other studies indicate that a cutoff score of 13 or greater would be more appropriate for identifying women who have clinical depression and would benefit from intervention or treatment.

Ideally we would like to be able to identify all women with perinatal depression; however, using to a toll which is not specific enough may lead to unnecessary referrals to mental health providers.  Given the limited numbers of providers trained to treat perinatal mood disorders, this approach may place a considerable strain on health care services and may make it even more difficult for women in need of treatment to get appropriate treatment in a timely fashion.

Various reports have also suggested that using the EPDS at multiple time points may help to improve its usefulness as a screening tool.  In a recent study, the EPDS was used to identify women with depression during pregnancy. The questionnaire was completed during the first prenatal visit (typically at 8 to 12 weeks of gestation) and then again 2 weeks later (during a telephone follow-up call).

Regardless of which of several cut-off scores on the EPDS was used to define a “high” scorer, approximately 50% of women reporting a high EPDS score at their first obstetric visit no longer scored “high” two weeks later. Common reasons given for their mood improvement included reduced morning sickness, reassuring results from routine tests (e.g., ultrasounds), fear of miscarriage subsiding, and a sense of reassurance following their first visit.

Clinically it can be very difficult to distinguish between distress and depression in this setting.  Pregnancy is an emotionally charged time, and many women report distress or changes in mood which may be quite normal in this setting. This is especially true early in pregnancy when women are concerned about the possibility of miscarriage in the early part of pregnancy.  In addition, pregnancy-related tests are likely to generate some level of anxiety.

Although everyone seems to agree on the importance of identifying women at risk for perinatal depression, we have yet to agree on how to best screen this population.  This study clearly indicates that screening with the EPDS during the first trimester is likely to lead to an over-identification of women with depression.  Repeat screening would improve the accuracy of this instrument.  However, other questions remain.  For example, would screening during the second or third trimester yield more stable result?

Although the Edinburgh Postnatal Depression Scale is the tool most commonly used to screen for depression during the pregnancy and the postpartum period, there are clearly inconsistencies in the use of this tool which may influence research outcomes and treatment recommendations. Further research will help to better define the use of this tool for screening women during pregnancy.

Ruta Nonacs, MD PhD

Matthey S, Ross-Hamid C. Repeat testing on the Edinburgh Depression Scale and the HADS-A in pregnancy: Differentiating between transient and enduring distress.  J Affect Disord. 2012 Jun 11. [Epub ahead of print]

Murray D, Cox JL. Screening for depression during pregnancy with the Edinburgh Depression Scale (EPDS). J Repro Infant Psychol 1990: 8, 99-107.