Do not over stretch the body.
Avoid postures that stress tummy muscles.
Postures that involves balancing should be done very carefully.
If any kind of pain is felt during exercise, then it should not be repeated again.
Here are some yoga exercises which are useful during labor and birth:
Downward Facing Dog
This is good for labor than child birth, as leg muscles gets more pressure during labor. This exercise helps in releasing pressure from the sacroiliac joints and stretches out the spine, and helps in relieving back pain.
There are two types of poses in 'Downward facing dog', one is full downward dog, which is beneficial in the initial stages of labor. Whereas the second pose is modified downward facing dog, which can be done by placing hands on chair. This keeps pressure on hip and back muscles.
This pose stretches the spine and lower back - one of the best position for childbirth. To do this, one needs to get down on her hands and knees, with shoulders parallel to your wrist. Keep your arms straight and as you inhale, slowly draw your hip upwards and roll your shoulders back and look up. Repeat this four to six times in a day.
To do this exercise, move your knees apart and rest your hip on your heels. Now bend your elbow and rest your head on your hand. Stay in this position and breathe in and out three to five times.