Yoga could reduce the risk of expectant mothers developing anxiety and depression, according to the first study on this subject.
Stress during pregnancy is related to negative outcomes for both mother and child.
Premature birth, low birth weight and increased developmental and behavioral problems in the child as a toddler and adolescent have all been linked to stress. High levels of anxiety during pregnancy can also lead to postnatal depression, which in turn is linked to risk of the mother developing depression in later life.
"There is a growing body of evidence that maternal antenatal anxiety may increase the risk of preterm delivery and the likelihood of giving birth to a low birth weight child," says James Newham, who carried out the research as a PhD student at Tommy's Maternal and Fetal Health Research Centre at the University of Manchester in the UK.
"If we can reduce these risk factors, and perhaps reduce the rate of postnatal mood disorders in mothers and negative health outcomes in their offspring, then that can only be a good thing."
Yoga already common among pregnant women, despite no previous evidence
Yoga is often recommended to pregnant women by medical professionals on the assumption that it may help in reducing stress, but this has never been put to the test, scientifically.
"It is surprising this has never been looked at before. We have long believed that it works but no research had been done to back up the theory," says Dr. Newham.
"We have now gone some way to prove that it can help," he confirms. "It was not a small effect either. This has the potential to really help mothers who are feeling anxious about their pregnancy."
Dr. Newham and his colleagues studied 59 women who were pregnant with their first child. The researchers asked these expectant moms to self-report their emotional state throughout the yoga course.
One session of yoga reduces anxiety 'by a third'
The women were split into groups, some of whom took part in a weekly yoga session for 8 weeks, while the others had normal prenatal treatment.
From analyzing questionnaires completed by the participants - and performing stress hormone assessments on the yoga group - the researchers calculated that a single session of yoga reduced self-reported anxiety by a third and stress hormone levels by 14%.
The stress-defeating powers of yoga also did not diminish across the duration of the 8-week course. The researchers found that the participants' stress and anxiety scores at the end of the course were similar to those reported in the first week of the intervention.
Prof. John Aplin, one of the senior investigators of the study - which is published in the journal Depression and Anxiety - and a yoga teacher himself, says:
"The results confirm what many who take part in yoga have suspected for a long time. There is also evidence yoga can reduce the need for pain relief during birth and the likelihood for delivery by emergency cesarean section.
Perhaps we should be looking at providing yoga classes on the [British National Health Service]. It would be relatively cheap to implement, could help mothers and their children be healthier, as well as reducing the costs of longer term health care."
Another recent study on yoga, reported by Medical News Today, found that yoga is also beneficial for improving the quality of life of breast cancer patients.