Depression in pregnant women appears to increase the risk that their children will experience depression when they are 18-years-old, according to a report published by JAMA Psychiatry.

According to the Centers for Disease Control and Prevention (CDC), prenatal depression affects 8% of pregnant women in the US.

Depression in late adolescence is a worldwide public health issue and identifying early-life risk factors will be important to guide prevention and intervention efforts, according to the study background.

The study, conducted by researchers at the University of Bristol in the UK, examined possible associations between prenatal and postnatal depression in women and later depression of their children at age 18.

The researchers analyzed a UK community-based study population with data from more than 4,500 parents and their adolescent children.

The findings show that children were more likely to have depression at age 18 if their mothers were depressed during the pregnancy, where depression was defined as increases in prenatal (also known as antenatal) maternal depression scores measured on self-reported depression questionnaires.

Postnatal depression and disadvantaged families

Postnatal depression was also a risk factor among mothers with low education because their children were also more likely to have depression based on increases in depression scores, according to the study.

Paternal postnatal depression also influenced an adolescent's chances of suffering from depression, but this was limited to the offspring of fathers with low education.

The study is believed to be the first to test the relative effects of depressive symptoms antenatally and postnatally on offspring depression at age 18.

The results appear robust, as this study included a large sample and long-term follow-up. Additionally, because the maternal depression had been recorded 18 years previously, reverse causality could be ruled out.

The connection between maternal antenatal or postnatal depression is more marked in mothers with low education. The study notes that maternal education indicates multiple sources of psychosocial support, for example, mothers are more likely to access child care. It also assumes that educated women will have more positive home environments, which in turn can be protective in the context of depression.

This study suggests that the risks associated with both prenatal and postnatal depression are different. While prenatal depression is an independent risk factor for offspring depression, postnatal depression may be a risk factor, but only in disadvantaged families.

The study concludes:

"The findings have important implications for the nature and timing of interventions aimed at preventing depression in the offspring of depressed mothers. In particular, the findings suggest that treating depression in pregnancy, irrespective of background, may be most effective."

Professor Rebecca M. Pearson and her colleagues note that further work is needed to understand why postnatally depressed mothers with low education are particularly at risk, but they suggest it may be beneficial to prioritize support for them.