Women with perinatal depression have an elevated mortality risk

Women who suffer depression during or after pregnancy have a higher risk of death by both natural and unnatural causes, a new study of childbirth in Sweden published in The BMJ reports. The increased risk peaks in the month after diagnosis but remains elevated for as long as 18 years afterwards.

Women who develop perinatal depression, which is to say depression during pregnancy or shortly after childbirth, are generally twice as likely to die of natural or, as in most cases, unnatural causes. They are six times more likely to commit than women without this form of depression. The increase in risk peaks in the 30 days following diagnosis but remains elevated for up to 18 years later.

These are the results of a large cohort study that used data from the Swedish Medical Birth Register, which effectively contains all births in Sweden since 1973.

Basing their study on women who had live births between 2001 and 2018, the researchers compared over 86,500 women diagnosed with perinatal depression, during pregnancy or up to one year after childbirth, with over 865,500 matched controls of the same age who had given birth the same year.

This is a cohort study, and although it can't prove any causality, it's the largest and most comprehensive study in its field. I believe that our study clearly shows that these women have an elevated mortality risk and that this is an extremely important issue."

Qing Shen, affiliated researcher at the Institute of Environmental Medicine, Karolinska Institutet and one of the principal authors of the study

The risk was highest for the women diagnosed with postpartum depression (depression after childbirth), corroborating the findings of previous smaller studies. Women diagnosed with antepartum depression (depression during pregnancy) have not been studied as much, so the knowledge base there is smaller. Dr Shen and her colleagues can now show that women with antepartum depression also have an elevated mortality risk, albeit not as high.

On comparing the mortality risk among women with perinatal depression who had had psychiatric problems even before pregnancy with women who had not had such issues, the researchers found that it was the same for both groups.

"Our recommendation is therefore not to discontinue effective psychiatric treatment during pregnancy," says Dr Shen.

The women who were diagnosed with perinatal depression tended to have been born in the Nordic region and have a shorter education history and lower incomes than women without such a diagnosis.

"One hypothesis is that these women seek help differently or were offered screening service postpartum not to the same extent, which means that their depression develops and is worse once it has been detected," says last author Donghao Lu, assistant professor at the Institute of Environmental Medicine, Karolinska Institutet. "Our view is that these women are particularly vulnerable and should be the focus of future interventions."

However, rather than introducing new measures, Dr Lu, argues that it is a matter of making better use of those already in place.

"Sweden already has many excellent tools, such as a postpartum questionnaire to screen the symptoms of postpartum depression," says Donghao Lu. "We need to stress how important it is for all pregnant women are offered screening, both postpartum and antepartum, and provided necessary, evidence-based care and support."

The study was financed by several bodies, including the Swedish Research Council for Health, Working Life and Welfare (Forte), the Swedish Research Council, Karolinska Institutet's Strategic Research Area in Epidemiology and Biostatistics (SFOepi) and the Icelandic Research Fund.