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Postnatal depression far more common in previous sufferers

Target preventive measures at specific groups of vulnerable women, urge researchers

Louise Prime

Wednesday, 27 September 2017

Although postpartum affective disorder (AD) occurs in just six in every thousand childbirths to women who have no history of psychiatric episodes, it affects more than a fifth of women with a history of hospital contact for depression after a previous birth and almost one in seven of those who took antidepressants after a first birth, researchers have discovered. The authors of the study,* published in PLoS Medicine, said their findings underline the necessity of preventive measures targeted at specific vulnerable groups.

A research team led from Copenhagen, Denmark, pointed out that for many of the 5%-15% of all women who experience postpartum depression (PPD), this is their first psychiatric disorder. They set out to estimate the incidence of AD (which they defined as an antidepressant prescription fill, or hospital contact for depression, within six months after birth), duration of treatment, and rate of subsequent postpartum AD and other affective episodes in a nationwide cohort of women with no prior psychiatric history.

They linked information from several Danish national registers, to construct a cohort of 457,317 primiparous mothers with first birth (and subsequent births) from 1 January 1996 to 31 December 2013). None of the women had prior psychiatric hospital contacts and/or prior use of antidepressants.

Over the 18-year study period, this Danish cohort had a total of 789,068 births, and there were 4,550 (0.6%) postpartum episodes of AD. The researchers reported that one year after the initiation of treatment for their first episode, 27.9% of women were still in treatment; and that after four years, this had fallen to 5.4%.

The rate of recurrence of postpartum AD with later births was 21% for women who had had hospital contact for depression after a first birth, and 15% for women who had taken antidepressants after a first birth. Once the study authors had adjusted for year of birth and the women’s age, they calculated that – compared with women with no history of postpartum AD – women with PPD hospital contact after first birth had a 46.4 times higher rate of a recurrent postpartum episode after their second birth, and women with postpartum antidepressant medication had a 26.9 times higher rate.

They commented: “In this study, an episode of postpartum AD was observed for 0.6% of childbirths among women with no prior psychiatric history. The observed episodes were characterised by a relatively short treatment duration, yet the women had a notably high rate of later AD and recurrent episodes of postpartum AD. The recurrence risk of postpartum AD was markedly higher among women with PPD hospital contact after first birth compared to women with postpartum antidepressant medication after first birth.”

They concluded: “[Our] study … underlines the seriousness of single initial episodes and highlights the necessity of both primary and secondary preventive measures, of which several exist.”

* Rasmussen M-LH, Strøm M, Wohlfahrt J, et al. Risk, treatment duration, and recurrence risk of postpartum affective disorder in women with no prior psychiatric history: A population-based cohort study. PLoS Med 2017; 14(9): e1002392. DOI: 10.1371/journal.pmed.1002392.

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