Exercising during pregnancy and after giving birth may help to reduce symptoms of postnatal depression, new research suggests.

Postnatal depression generally occurs during the first year after a baby is born. Symptoms can include low moods, feelings of sadness and loneliness, frequent crying for no apparent reason, anxiety, feeling unable to cope and lacking energy.

Until now, there has been inconsistent evidence about the effect of exercise on postnatal depression, so researchers in Spain and Chile decided to look into this further.

They analysed 12 studies on this topic that were carried out between January 1990 and May 2016. The studies involved over 1,400 women and were carried out in a number of countries, including the UK, the US and China.

All of the studies involved healthy women who were either pregnant or had given birth between six weeks and 18 months previously.

Different types of exercise undertaken by the women were included, such as walking, cardiovascular exercises and yoga.

The researchers found that physical activity during pregnancy and the postpartum period was linked with a lower incidence of postnatal depression symptoms.

They said these findings are important as they ‘provide evidence about the effectiveness of physical activity on the mitigation of postpartum depression symptoms'.

"Consequently, our study provides support for the recommendation to advise pregnant women and new mothers to engage in exercise programmes as an effective and safe strategy to achieve better psychological wellbeing and to avoid postpartum depressive symptoms," they concluded.

Details of these findings are published in the journal, Birth.