Genetic screening for postnatal depression

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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Treatment of PTSD following childbirth: the importance of context

By Kirstie McKenzie-McHarg, Clinical Psychologist and founding member

I work as a clinical psychologist and manage a perinatal psychology service in the UK. A basic dilemma that exists when treating PTSD following childbirth (PTSD FC) is that of whether the presentation of PTSD in the perinatal population the same as, or different from, PTSD caused by other events?  If the presentation is the same, we can utilise existing approved treatments.  If it is different, we may need to adapt our approaches to allow for these differences.  Trauma-focused cognitive behaviour therapy (CBT) is a PTSD treatment recommended by NICE guidelines. A paper by Ayers, McKenzie-McHarg & Eagle (2007) presents case studies which suggest that standard CBT approaches to women experiencing PTSD FC are effective and appropriate to use with this population.

However, the context of PTSD FC differs from that of PTSD following other events.  In PTSD FC, women are expected to take home a dependent newborn and to care for the baby.  For some women, the baby is a lasting reminder of their traumatic birth experience, and bonding and attachment may be affected.  There are significant postnatal hormonal changes for women.  Childbirth itself is considered by society to be a positive event, unlike any other stressor leading to PTSD such as war, assault or traffic accident. Therefore women may experience others as lacking in understanding, making comments such as ‘aren’t you lucky, you have a beautiful baby’.  There are very often sexual problems for women experiencing PTSD FC.  All of these specific difficulties are in addition to the normal postnatal background of extreme fatigue, increased social isolation, decreased independence and increased responsibility.  As such, it is important that the postnatal context of women with PTSD FC is taken into account when intervention is planned.

Clinicians working with PTSD in the perinatal context therefore need to consider how to work effectively when the mother may need to bring the baby to every session; for example, if the mother is highly anxious and therefore cannot leave her baby, or if she is breastfeeding.  There is also a need to recognise that some women will experience a tension between significant anger and resentment at the changes in her status and health, and simultaneously experiencing an overwhelming and confusing protective instinct for an infant she may resent.

The clinical space therefore must provide a safe and containing environment in which new mothers can express their conflicting emotions, and admit to potentially shaming or even dangerous thoughts about themselves and their baby.  While the creation of this safe space presents a challenge when working clinically with any individual with PTSD (due to their avoidance of discussing the trauma) it is additionally difficult in a postnatal population.  This is because many women fear that admitting negative emotions towards their baby may result in a referral to social services and the subsequent loss of their baby.  In summary, while the broad therapeutic approach we use for intervention for PTSD may remain the same, consideration of the perinatal context is critical.