Intended for healthcare professionals

Letters

Depressed mood during pregnancy and after childbirth

BMJ 2001; 323 doi: https://doi.org/10.1136/bmj.323.7325.1367/a (Published 08 December 2001) Cite this as: BMJ 2001;323:1367

Time points for assessing perinatal mood must be optimised

  1. Julia Lappin, senior house officer in psychiatry (julia_lappin{at}hotmail.com)
  1. Maudsley Hospital, London SE5 8AZ
  2. Rotunda Hospital, Dublin 1, Republic of Ireland
  3. Mater Misericordiae Hospital, Dublin 7
  4. University Hospital, Queens Medical Centre, Nottingham NG7 2UH
  5. University Hospital, Nottingham NG7 2UH
  6. Division of Psychiatry, University of Bristol, Bristol BS2 8DZ
  7. Unit of Paediatric and Perinatal Epidemiology, Division of Child Health, University of Bristol, Bristol BS8 1TQ
  8. Department of Women's Health and Care of the Newborn, North Bristol NHS Trust, Southmead Hospital, Bristol BS10 5NB
  9. Mother and Baby Unit, Barrow Hospital, Barrow Gurney, Bristol BS48 3SG

    EDITOR—Evans et al studied perinatal mood using the Edinburgh postnatal depression scale.1 They claim that symptoms of depression are not more common or severe after childbirth than during pregnancy and that depression during pregnancy is more common than postnatal depression. These two findings have potentially far reaching implications, but caution is needed in using the data to draw these conclusions.

    The Edinburgh postnatal depression scale has been validated for use only in the early postpartum period and predicts depression correctly in most (73%) women with a score above 12.2 Analysis of scores below this threshold should be made with care: variability of 1–2 points then has not been proved to indicate severity of depression. The interpretation of raised mean scores (such as 6.72 at 32 weeks of pregnancy compared with 5.84 at 8 weeks post partum) as indicating more severe depression may then be inaccurate. The difference in mean scores should be considered with respect only to those scores above 12, but the authors did not do this. Instead they evaluated change in average score.

    Factors assessed by checklists of depressive symptoms tend to be associated with many psychiatric disturbances, including anxiety and related stresses such as adverse living conditions.3 Thus non-specific stressors leading to higher levels of anxiety could transiently increase a woman's score on the Edinburgh postnatal depression scale at any time. Two of the time points chosen (18 and 32 weeks of pregnancy) coincide with times of contact with staff for antenatal screening and discussion of the birth plan. Having to consider these choices adds to mounting anxiety secondary to many factors, including experience of the pregnancy as a loss of control and anticipation of a major life transition.

    The study found more women to be depressed at 32 weeks of pregnancy than at 8 weeks post partum. There may, however, be a higher frequency of postpartum depression before 8 weeks that the study did not detect. Postpartum depression presents most commonly within a month of childbirth; swift recognition and appropriate treatment would lead to an improvement in symptoms by 8 weeks post partum.

    The authors are right to highlight the importance of assessing perinatal mood, but the times for administering the Edinburgh postnatal depression scale should be carefully selected to avoid a false picture being given.

    References

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    3. 3.

    Treatment for depression is important confounding variable

    1. J Sheehan, consultant in liaison psychiatry,
    2. F M Crotty, special lecturer in psychiatry (fcrotty{at}mater.ie)
    1. Maudsley Hospital, London SE5 8AZ
    2. Rotunda Hospital, Dublin 1, Republic of Ireland
    3. Mater Misericordiae Hospital, Dublin 7
    4. University Hospital, Queens Medical Centre, Nottingham NG7 2UH
    5. University Hospital, Nottingham NG7 2UH
    6. Division of Psychiatry, University of Bristol, Bristol BS2 8DZ
    7. Unit of Paediatric and Perinatal Epidemiology, Division of Child Health, University of Bristol, Bristol BS8 1TQ
    8. Department of Women's Health and Care of the Newborn, North Bristol NHS Trust, Southmead Hospital, Bristol BS10 5NB
    9. Mother and Baby Unit, Barrow Hospital, Barrow Gurney, Bristol BS48 3SG

      EDITOR—Evans et al reported that scores on the Edinburgh postnatal depression scale were higher during pregnancy than at 8 weeks or 8 months post partum.1 No information is provided, however, on the number of women in the postpartum group who were receiving treatment for depression. Treatment includes both pharmacological and non-pharmacological means. The absence of this information brings the results of the study into question.

      The effect of treatment is an important confounding variable. During pregnancy women are reluctant to take antidepressant drugs; after the birth, however, many will have already attended their general practitioners and have started treatment by 8 weeks post partum, when the postnatal depression score was measured. The conclusion that symptoms of depression are not more common or severe after childbirth than during pregnancy cannot be supported unless information regarding numbers of women receiving treatment for depression are included.

      References

      1. 1.

      Data do not support idea that depression is more common antenatally than postnatally

      1. M R Oates, senior lecturer in perinatal psychiatry (Margaret.Oates{at}nottingham.ac.uk),
      2. A Lee, consultant psychiatrist
      1. Maudsley Hospital, London SE5 8AZ
      2. Rotunda Hospital, Dublin 1, Republic of Ireland
      3. Mater Misericordiae Hospital, Dublin 7
      4. University Hospital, Queens Medical Centre, Nottingham NG7 2UH
      5. University Hospital, Nottingham NG7 2UH
      6. Division of Psychiatry, University of Bristol, Bristol BS2 8DZ
      7. Unit of Paediatric and Perinatal Epidemiology, Division of Child Health, University of Bristol, Bristol BS8 1TQ
      8. Department of Women's Health and Care of the Newborn, North Bristol NHS Trust, Southmead Hospital, Bristol BS10 5NB
      9. Mother and Baby Unit, Barrow Hospital, Barrow Gurney, Bristol BS48 3SG

        EDITOR—In Evans et al's study both the total scores on the Edinburgh postnatal depression scale and the number of women scoring above 12 rose through pregnancy and fell after delivery.1 The authors are generally careful not to use the terms depression and illness but refer to depressive symptoms. They acknowledge that a cut-off score on a screening schedule does not give a clinical diagnosis, but this caution is abandoned in their conclusion—that antenatal depression is commoner than postnatal depression and that treatment would benefit the mother and infant. This was widely quoted in the media on the morning of publication.

        The findings do not support this conclusion, showing only that scores on the depression scale rise during pregnancy. In the absence of normative data on common emotional changes during pregnancy, and the properties of items on the scale in relation to established dimensions of perinatal depressive illness, we cannot ascertain how many women had a depressive episode that required treatment. This is highlighted by the observation that half of the women who scored above the threshold at 32 weeks scored below it at 8 weeks post partum, presumably without treatment.

        The comment that the benefits of antidepressants may outweigh the risks in pregnancy could be seen to encourage their use in late pregnancy. Although the risks of teratogenesis are low, there is no evidence on the safety of antidepressants in late pregnancy.

        An alternative and simpler explanation for rising scores during pregnancy is that certain items on the Edinburgh postnatal depression scale pick up common concerns in pregnancy. For example, item four relates to feeling worried and anxious for no good reason, while item six relates to coping less well than usual. We are concerned that non-specialist readers will misunderstand this study as relating to depressive illness severe enough to require specialist treatment. To state that serious depressive disorder is more common and more severe antenatally than postnatally is not supported by these data.

        What the authors have shown is the need for rigorous clinical research into the relation between cut-off scores on screening schedules and the nature of depressive disorder. The possible treatment needs of those identified with screening schedules should also be investigated.

        References

        1. 1.

        Authors' reply

        1. Jonathan Evans, consultant senior lecturer (j.evans{at}bristol.ac.uk),
        2. Jon Heron, research assistant,
        3. Jean Golding, professor of paediatric epidemiology,
        4. Helen Francomb, midwife,
        5. Sarah Oke, consultant psychiatrist the Avon Longitudinal Study of Parents and Children (ALSPAC) Study Team.
        1. Maudsley Hospital, London SE5 8AZ
        2. Rotunda Hospital, Dublin 1, Republic of Ireland
        3. Mater Misericordiae Hospital, Dublin 7
        4. University Hospital, Queens Medical Centre, Nottingham NG7 2UH
        5. University Hospital, Nottingham NG7 2UH
        6. Division of Psychiatry, University of Bristol, Bristol BS2 8DZ
        7. Unit of Paediatric and Perinatal Epidemiology, Division of Child Health, University of Bristol, Bristol BS8 1TQ
        8. Department of Women's Health and Care of the Newborn, North Bristol NHS Trust, Southmead Hospital, Bristol BS10 5NB
        9. Mother and Baby Unit, Barrow Hospital, Barrow Gurney, Bristol BS48 3SG

          EDITOR—We agree that scoring above a threshold on the Edinburgh postnatal depression scale is not the same as being diagnosed as having depression. The scale has been validated during pregnancy against a standardised clinical interview, and we referred to this in the paper.1 The scale therefore gives a reasonable estimate of the prevalence of depression during pregnancy and does not just detect minor emotional fluctuations.

          The mean individual item scores do not differ between pregnancy and the postpartum period, and more women have high or very high scores during pregnancy than after childbirth. Lappin suggests comparing mean scores only for those above the threshold for depression during pregnancy and after childbirth; these scores were 15.57 at 32 weeks of pregnancy and 15.85 at 8 weeks post partum, which suggests no difference in severity of depression between these two times.

          There is no evidence of discontinuity between depressive symptoms and depressive disorder in general populations.2 A scale may give a better indication of severity than a clinical diagnosis: the range of severity is considerable even within the category major depressive disorder. Validation studies of the Edinburgh postnatal depression scale indicate that scores differ between people with minor, moderate, and major depressive disorder, and the scale was also sensitive to change in the severity of depression over time.

          Our statement that the benefits of using antidepressants might outweigh the risks for women with severe depression does not encourage the use of antidepressants during pregnancy without careful consideration. We have highlighted the need for research into safe and effective treatments of depression during pregnancy as well as the consequences of untreated depression at this time.

          Two letters point out that treatment of postpartum depression may have been partly responsible for our apparently lower rates of depression in this period. Although this is possible, we think it is unlikely that depression would have been recognised and responded to so quickly. Only 0.6% of all mothers were taking antidepressants post partum and were below the threshold for depression at 8 weeks post partum. Even if we assume that all of these would have been above the threshold at 6 weeks post partum there would still be fewer above the threshold post partum than at 32 weeks of pregnancy.

          Finally, the timing of the measures, as pointed out, coincided with obstetric care. Scores may certainly have been higher or lower at other times, but for the purposes of screening these times are the most practical to use.

          We are confident that our paper emphasises that symptoms of depression are more common during pregnancy. It is important that general practitioners, health visitors, and others are aware that pregnant women are not protected from common mental disorder.

          References

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