If you were running before you got pregnant, it’s probably safe to continue — but make sure you breathe deeply and stay hydrated. Talk to your doc about your routine, since you’ll probably have to make some adjustments. (Yes, that means put that marathon training on hold!) Also, if you have preeclampsia, are at risk of a preterm birth or have some pregnancy complications (like bleeding), you may need to take the gym shorts and sneakers off for the next nine months. And of course, if you’ve never worked out before, now probably isn’t the best time to start a new exercise routine.