Postnatal depression (PND) affects at least 10% of women (Howard et al, 2014), and awareness of the importance of perinatal mental health is increasing (the Mental Elf recently published a special blog for the second UK Maternal Mental Health Matters Awareness Week).
However, the term PND is a giant umbrella covering many different symptoms and severities. When a condition is common, it’s important to identify how parents are affected and which treatments are likely to be safest and most efficacious.
Previous work has been conducted to potentially classify different types of PND, and unsurprisingly this has suggested that children are most affected when maternal depression is both severe and long-lasting.
Data were taken from participants in the Avon Longitudinal Study of Parents and Children (ALSPAC).
The presence of PND was assessed using the Edinburgh Postnatal Depression Scale (EPDS) in 9,848 mothers at 2 and 8 months after childbirth (and data on depression were available for 6,182 mothers 11 years after childbirth).
Scores on the EPDS were divided into moderate (13-14 points), marked (15-16), and severe (17+) depression. PND was defined as persistent if it was present at both 2 and 8 months after childbirth.
The only variable controlled for was maternal education, defined as high if education continued after age 16 (3,841 [39%]).
Children were assessed for behavioural problems using the Rutter Total Problems Scale at 3 ½ years (8,419 children, scale completed by their mother), educational attainment was recorded using GCSE mathematics grade at age 16 (5,198), and depression in children was self-reported at age 18 (3,613).
Linear growth modelling was used to examine mothers’ EPDS scores over time. Seven levels of PND severity were defined based on score and persistence, and regression was used to explore a dose-response relationship between PND and the three child outcomes.
Most vulnerable mothers and children
- The most vulnerable group consisted of women meeting criteria for moderate and severe postpartum depression both at 2 months and 8 months after delivery
- These women were more likely to continue to have depression 11 years later;
- Their children also had:
- a 4-fold increased risk of having behavioural problems between ages 3 and 4 years,
- a 2-fold increased risk of having lower mathematics grades at 16 years,
- and a 7-fold increased risk of depression at 18 years.
Depression in mothers
- Of the original 9,848 mothers, 83 (0.8%) were recorded as having persistent and severe depression 8 months after childbirth (mean EPDS score 19.95)
- Their mean EPDS score remained high up to 11 years later (37 mothers, mean score 14.49)
- There was a considerable decrease in the number of responses from participants at both 16 (4,941) and 18 years (3,486) after childbirth.
- Presence of behavioural problems in their children aged 3½ was significantly associated with all levels of PND, including persistent and severe (p < 0.001)
- Low GCSE mathematics grades (p < 0.01) and offspring depression at 18 years of age (p < 0.001) were also significantly linked with severe and persistent PND
- There was little association between negative child outcomes and cases of PND that were denoted as moderate, marked, or not persistent.
Strengths and limitations
This study highlights the long-term impact of PND on the outcomes of offspring. The authors estimated that less than 1% of the sample used antidepressants and psychological treatments were not widely available. Therefore this can be considered a naturalistic study of what happens when postnatal depression is left untreated. It builds on current guidelines for perinatal screening (National Institute for Health and Care Excellence, 2014), proposing that extending this period to detect persistent depression would be beneficial. However, there are several points that may dispute the contribution this paper makes to an already crowded field.
Use of ALSPAC is common among other studies. Due to its longevity there was a substantial attrition rate, likely biased against our group of interest. The proportion of women who experienced prolonged depression may be underestimated.
The authors acknowledge the small number of women with severe and persistent depression, and the difficulty in controlling for confounders other than maternal education. However, their influence may call into question the validity of the results. Antenatal depression contributes significantly to adverse child outcomes (Glover, 2014), and the incidence in this sample is unknown. The Mental Elf has highlighted the comparable impact of paternal depression. The list goes on: socioeconomic status, sex of the baby, and other life events are all linked (Sirin, 2005; Whiteford et al., 2013). The authors recognise the small sample size limits exploration of these confounding factors, and we do not know if some of these may be more influential than PND itself.
Conclusions and implications for practice
- This study highlights that women who experience PND for more than a few months after childbirth will continue to suffer from depression when left untreated
- Children are at a greater risk of depression and of not fulfilling their educational potential when their mother experiences persistent, and especially severe, depression
- There are likely to be other factors that also affect child outcomes; however this study suggests that services target resources to identify and treat mothers whose depression is severe and does not resolve by the eighth month after childbirth.
Netsi E, Pearson RM, Murray L, Cooper P, Craske MG, Stein A. (2018) Association of persistent and severe postnatal depression with child outcomes. JAMA Psychiatry. 2018;75(3):247–253. doi:10.1001/jamapsychiatry.2017.4363
Domoney J. A closer look at perinatal depression. The Mental Elf, 29 Jun 2017.
Glover, V. Maternal depression, anxiety and stress during pregnancy and child outcome; what needs to be done. Best Practice & Research Clinical Obstetrics & Gynaecology. 2014;28(1):25-35. [PubMed Abstract]
Howard LM, Molyneaux E, Dennis C-L, Rochat T, Stein A, Milgrom J. (2014) Non-psychotic mental disorders in the perinatal period. Lancet. 2014;384(9956):1775-1788. [PubMed Abstract]
National Institute for Health and Care Excellence. (2014) Antenatal and Postnatal Mental Health Guidelines. Clinical Guidelines CG192. NICE, 2014. https://www.nice.org.uk/guidance/cg192
Pariente C, Godfrey-Issacs L, Lamdin H. (2018) The key to maternal mental health? Make it a collective experience again #maternalmhmatters. The Mental Elf, 5 May 2018.
Sirin SR. (2005) Socioeconomic status and academic achievement: A meta-analytic review of research. Review of Educational Research. 2005;75:417–453.
Whiteford HA, Degenhardt L, Rehm J, et al. (2013) Global burden of disease attributable to mental and substance use disorders: findings from the Global Burden of Disease Study 2010. Lancet. 2013;382:1575–86. [PubMed Abstract]