Ardha Titali Asan (Half Butterfly)
Sit with your legs outstretched. Bend your right leg and place your right foot as far up on your left thigh as possible, placing your right hand on top of your right knee. Hold the toes of your right foot with your left hand. Without moving your torso, inhale while gently bringing your right knee up to your chest. Use your right hand to lift your leg, not your leg muscles. Exhale and lower your leg, attempting to touch the floor with your right knee.
Gently do 10 movements up and down, then switch legs and do another 10. Remember: don't strain.
This pose loosens your hip and knee joints, which may help ease childbirth.
You should never exercise to the point of discomfort, especially while pregnant.
Working out until you are sore, exhausted and straining to breathe creates free radicals, which can cause disease, premature aging, and weaken your immune system. If you work out so intensely that you must take a few days off from exercise, you are increasing wear and tear on your body and will actually slow down your metabolism, causing you to have less energy and possibly even gain weight.