
Running has a bad rap among the Old Wives for causing miscarriage, birth defects, and heck, probably ADD. You name it.
Good thing we've got the majority of the medical community behind the sport as a wonderful means of exercise while pregnant. And, no. There's no medical backup stating that running causes miscarriage or compromises the baby's health, if you follow some basic rules and stay in tune with your baby-making body.
1) Don't get too hot. For the same reason as not getting into the hot tub, very high tempuratures are not good for baby.
2) Run slow. Growing a baby is a huge job, so keep it easy-peasy. Walk at least twice, and really tune in to your physiology.
3) Use a Heart Rate Monitor. If you're not the best at knowing what your body is telling you, using a HRM to keep your heart rate from soaring is a good bet. Some books say keep it below 140 bpm (beats per minute) but for some women that's hardly breaking a jog.
More rules and tips can be found in this excellent article by Runner's World, about the pregnant runner.
Upon discovering you are expecting, some of us are happy to put the running shoes away for a bit. But you don't have to. Simply put, if you have been a runner before your pregnancy, keep running. If not, it's probably not the time to start. There are lots of other options for keeping svelte (but not too svelte; after all it is your goal to GAIN weight!) Get to the gym for pilates, yoga, and even weight lifting. That's right, lifting weights is good for you!
After all, you're going to be lifting your baby hundreds of times in the first year after giving birth - you'd better get in shape!