You can ask your doctor or midwife to help you check for this condition after birth. It is a very simple check. A diastasis recti will usually clear up on its own but there are also exercises you can do to help treat the separation. Occasionally an umbilical hernia will occur necessitating surgery.
In pregnancy you will want to avoid strenuous abdominal exercises after the first trimester. Postpartum you will need to screen for this separation before returning to working out your abdominal muscles. Your practitioner can help you find appropriate exercises until you are healed.