The Weight-Control Information Network suggest the following to help women stay healthy both while they are pregnant and after their child is born: speak to your healthcare provider about what exercises are safe to perform during pregnancy, return to normal exercise after the baby is born (as soon as your doctor approves such activities), drink plenty of fluids when exercising, use caution when exercising in warm weather, eat a balanced diet both during and after the pregnancy, and if possible, breast feed to aid in burning calories.
National Institutes of Health, October 2015