Muscle separation in the abdominal area is most common during pregnancy. As the fetus grows, the muscles in the abdominal wall are gradually pushed and pulled apart. During pregnancy, the skin and muscles are pushed taut, but they become soft and loose after childbirth. The muscles are unable to contract and tighten once they are loosened during pregnancy, meaning that no amount of exercise can correct the problem, known as diastasis recti. Surgical intervention is necessary to re-tighten the muscles.