London, Oct 1: Depression during pregnancy may increase the risk of behavioural and emotional problems in children, according to new research in low and middle income countries.
Depression in pregnancy is thought to affect up to one in five women globally in the late stages of pregnancy and shortly after birth.
It is characterised by low mood and feelings of hopelessness, and is brought on by a number of factors that can include life events such as bereavement, and changes in brain chemistry.
Researchers from Imperial College London found that depression or anxiety can reduce the enzyme in the placenta that breaks down the 'stress hormone' cortisol, possibly causing more foetal exposure to the hormone.
The foetus may also undergo epigenetic changes under stress, where underlying DNA stays the same but expression of that DNA is altered, affecting mental health during childhood.
"Our review of available literature suggests that treating the depression itself is crucial in reducing the risk to the child, as well as for helping the mother," said Vivette Glover from Imperial College London.
"It shows targeting specific symptoms of depression by using cognitive behavioural therapy, for example, can be useful in reducing depression and therefore its effect on the child," said Glover.
"However, there is a substantial lack of research specific to women in poorer countries, where interventions such as cognitive behavioural therapy may not be available," she said.
Glover added that in severely deprived regions where there are wars, political violence, food insecurity, and little help after natural disasters, healthcare workers have little time or resources to meet basic physical needs, let alone mental health ones like maternal depression.
The new review examined studies of mental health in children under five years old in low and middle income countries such as Bangladesh and Brazil.
Depression in mothers in low- and middle-income countries is common during and just after pregnancy, researchers said.
Women are more likely than in richer countries to experience intimate partner violence and have little social support.
Furthermore, unintended pregnancies are more common, as are malnourishment, infections, and crowded living conditions. The risk factors are often more intense and more common than in high-income countries.
These factors also intensify one another - for example, a malnourished mother or child may have too weak an immune system to fight an infection, exacerbating the mother's stress which then contributes to depression.
Maternal depression in these countries is also more likely to result in poor nutrition, increased substance use, inadequate antenatal care, pre-eclampsia, low birthweight, preterm delivery and suicide.
The study was published in The Lancet Psychiatry journal.