Pregnant women could strengthen their babies' lungs and nervous system by exercising, new research suggests.
American researchers conducted a small study into the impact of exercise and found potential benefits for unborn babies.
According to scientists, exercise may also help prevent cot death.
Dr Linda May, an assistant professor of anatomy at Kansas City University of Medicine and Biosciences, said her study had yielded "exciting" results.
"We tested foetal breathing movement and the way the baby's nervous system was developing," The Scotsman quoted her, as saying.
"When we compared babies whose mothers exercised with babies whose mothers had not exercised, we found wonderful differences.
"Foetal breathing movement and the nervous system were more mature in babies exposed to exercise," she added.
All the women involved in the study were 36 to 38 weeks pregnant and aged 20-35. The mothers-to-be were classified as exercisers if they exercised for at least 30 minutes three times a week.