New research shows that less than a third of mothers return to their pre-pregnancy fitness levels a year after giving birth. In a study published in the journal PLOS One, researchers at Martin Army Community Hospital in Georgia studied 460 females active in the military when they became pregnant. They found that only 30 percent of the participants had the same fitness levels a year after giving birth as before. And three-fourths of the women took three years to reach their pre-pregnancy fitness levels. Generally, women who have a healthy pregnancy and undergo vaginal deliveries can start exercising soon after delivery. C-sections and more complicated pregnancies might require longer delays. But the benefits of exercise for newborn mothers are numerous, including better sleep and mood, quicker loss of extra weight, and lower risk of postpartum depression.