The condition known as diastasis recti is usually not a life-long condition and should settle after several months. However, once cleared by your doctor, you can undertake few simple exercises to enhance the healing process.
The basic idea by doing these exercises is to strengthen the muscles which are suppose to meetup in the mid-line. Therefore, one such exercise which can be very effective is the pull-ins.
In order to do this, you need to lie flat on a firm surface with face up and the knees bent. The feet should be firmly touching the floor. Remember to support the head with a pillow. While keeping the hands on either side of the belly, you should take a deep breath. As you exhale, you need to pull the belly button towards the spine. While holding the belly button on this position, you should wait for at least 10 seconds. This can be repeated for 10 to 20 times depending on your tolerance level.
Hope this will be of help.