Issues for consideration by Rose Coates, PhD student, University of Sussex

I am doing research on conceptualising and screening for postnatal mental health problems and am writing in response to the recent publication of research by Engineer and colleagues identifying possible genetic markers for postnatal depression.  A lot of media reports interpreted this as leading to genetic screening for postnatal depression (e.g. Sky News) and I was contemplating what this means for mothers experiencing any kind of postnatal distress. On the one hand, any research into postnatal depression is welcome and raises awareness of how prevalent and debilitating it is. We also need to understand physiological vulnerability as well as psychological and social vulnerabilities. On the other hand, I have a number of concerns about the focus on genetic screening for postnatal depression.

My first concern is that not all women who screen positive will go on to develop postnatal depression. The potential value of genetic screening therefore needs to be balanced against the potential impact on women of being told they might get postnatal depression. Screening positive could increase stress and anxiety during pregnancy, which studies have shown is associated with preterm labour and poor infant outcomes (e.g. Schuurmans & Karrasch, 2013, Dunkel Schetter & Tanner. 2012). After birth, women might persistently worry about any feelings of distress and quick to pathologise symptoms that may be a normal part of the transition to motherhood.

My second concern is that some women who screen negative will go on to develop postnatal depression. In these circumstances, will women feel that their experience is less valid because the test gave them the all-clear? Will it be clear to women that the test is screening for only one marker of elevated risk for postnatal depression and not the many other forms of distress that women can and do experience e.g. anxiety, PTSD, bonding and adjustment disorders? Given the lack of knowledge and information about other forms of postnatal distress in the public sphere this seems unlikely. Beyond mothers, will midwives and health visitors be given enough training and time to fully understand and communicate these issues of the tests sensitivity and specificity?

My third concern and perhaps the most worrying aspect to me are reports in the media that the screen could be a time- and money-saving method of detecting mothers at risk of depression. The implication is that midwives and health visitors could use this test with new mothers in their care instead of asking about wellbeing and women disclosing feelings of distress. Many studies show that what mothers want, and what helps them through distress, is talking to someone supportive (e.g. Cuijpers et al., 2008). Of course there will always be some mothers who do not want to disclose their feelings but it is not certain that screening for increased genetic risk of depression will lead to improved help and support for this group anyway.

In my view, more research and consideration of the impact of screening on women is needed. As Engineer and colleagues take pains to acknowledge, their results are based on a small convenience sample and they assessed postnatal depression using a score of 10 or more on the Edinburgh Postnatal Depression Scale (EPDS).  Irrespective of the utility of using the EPDS to detect postnatal depression, the usual cut-off score is 13 or more, which likely accounts for their high prevalence of probable depression (24%). The EPDS was also given only once postpartum (4-6 weeks) so it is possible a number of women who screened positive may simply be experiencing transient distress. Matthey (2010) argues that two high scores on the EPDS, separated by two weeks, and combined with a clinical interview provide a more accurate assessment for ongoing depression. It is therefore important that we consider the impact of screening on women and the best way in which to do this.

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