According to the task force statement, “direct and indirect evidence support moderate certainty that screening for depression in pregnant and postpartum women is of moderate net benefit”, citing reductions in risk of depression of 28–59% in post-partum women who underwent screening. However, these conclusions are at odds with recommendations from other countries. Expert groups in Canada and the UK, for example, have evaluated the same body of literature and concluded that high-quality evidence to support routine perinatal screening for depression is scarce. Notably, as stated in the USPSTF report, five of the six studies included in the assessment of the effects of depression screening on health outcomes were of only fair quality, none compared simply screening plus usual care versus usual care alone, and the reduction in risk of depression in pregnant women was not statistically significant.
Furthermore, for a screening test to be suitable for use in clinical practice, it must be simple and accurate with an acceptable risk of false-positive and false-negative results. But the most commonly used screening instrument—the Edinburgh Postnatal Depression Scale—is lengthy to administer and has a positive predictive value for detecting major depressive disorder of just 47–64%, running the risk that a substantial proportion of women could be falsely labelled as having depression. This situation is potentially dangerous. Results of qualitative studies suggest that women are extremely concerned about depression screening, about the stigma associated with a diagnosis of depression, and that a positive result might lead to an automatic social service referral, and potentially removal of their baby. Only one trial in the USPSTF review reported on the potential harms of screening, but noted no harmful effects. Clearly, high-quality randomised controlled trials of screening programmes that include access to interventions, with a thorough assessment of the potential adverse effects, are needed before widespread screening can be advocated.
Information about the financial costs of perinatal depression screening is a glaring omission from the USPSTF statement. The high rate of false-positive screenings could also lead to costly referrals, unnecessary diagnostic assessments, and possibly treatment for some women incorrectly identified as depressed. Access to care is problematic in some countries, notably the USA, especially for marginalised people such as the large undocumented immigrant population, who cannot even get access to basic maternity care. Funds might be better spent on improving care for these disadvantaged groups.
Identification of perinatal depression is undoubtedly important. As highlighted in the Lancet Series on perinatal mental health, depressive disorders are common during pregnancy and the post-partum period: the point prevalence of major depressive disorder is about 5% during pregnancy and in the first 3 months after childbirth in women from high-income countries, and prevalence is generally higher in low-income and middle-income countries. Maternal depression is associated with a range of negative child outcomes, which can persist into adolescence and adulthood, and about a third of women who develop postnatal depression still have depression beyond the first year after giving birth. However, to merely focus on identification of depressive disorders during pregnancy and the post-partum period is a missed opportunity. Other mental health disorders can also occur—for example, studies suggest that anxiety disorders are more common than depressive disorders during pregnancy and the postnatal period—and the regular appointments that take place during pregnancy and post partum are an ideal opportunity to fully address the whole range of mental health disorders that can present during this time.
Routine screening for depressive disorders in pregnancy and post partum could potentially be harmful. The pregnancy and postnatal period is an opportunity to maximise the health of women and their families. But this needs to be done through sensitive enquiry in the context of a broader conversation about the physical and mental health wellbeing of mothers.