If you aren’t considered “at risk” for a complicated delivery, chances are that your obstetrician or midwife has told you exercising while pregnant is the healthy thing to do. Now, you might not actually feel like working up a sweat once you’re deep into the first trimester and plagued by fatigue, nausea and other fun things””but exercise might make you feel better, believe it or not! (Personally, the days the Morning Sickness Fairy seemed to forget about me were always days I went for a run or did some cardio at the gym.) Plus, exercise during pregnancy can prevent excess weight gain and help treat or prevent gestational diabetes.

Here are some guidelines for safely exercising while you’re pregnant:
1. Safety first.
Make sure your healthcare professional clears you to exercise””even if you assume exercising is fine, you’ll want to get an expert take on your specific situation. Also be sure to wear appropriate footwear and avoid lying flat on your back after the first trimester so that you don’t diminish blood flow to your brain and uterus.
2. Be mindful of how many calories you are burning.
Pregnancy would seem like one time in life when you don’t have to think so much about calories””but actually, you do have to worry about under-eating. If a 3-mile run burns 300 calories and your doctor told you that you should intake an extra 250 calories a day in your first trimester (a typical recommendation for a woman who did not begin pregnancy overweight or underweight), then you really need to be eating 550 calories above what you ate in a typical day pre-pregnancy. This doesn’t mean you should be gorging on ice cream sundaes and French fries, though””stick with extra fruits, vegetables, healthy fats like nuts and coconut or olive oil, and whole grain snacks. I ate a KIND bar a day during my third pregnancy (partly because they are healthy, partly because they are delicious!)
3. Hydrate, hydrate, hydrate!
It’s a good idea to drink extra water when you’re pregnant, anyway””dehydration can cause complications including premature contractions. Water loss from sweating during exercise further increases the need for adequate hydration. You might want to pop a NUUN electrolyte tablet in your water bottle just to be in the safe side, or drink a natural, sugar-free sport drink like Ultima Replenisher while you’re on that treadmill.
4. Now isn’t the time to train for your first marathon.
Stick with exercises you’re experienced at and scale them back as your baby and your belly grow. If you weren’t as physically active pre-pregnancy as you would have liked, prenatal yoga, walking and swimming are all great activities for moms to be.
5. Avoid wardrobe malfunctions.
Spandex might be all the rage when you’re not pregnant, but make sure you’re not wearing clothes that are too tight or too hot once you’re starting to show. You don’t want to get overheated! Also, be sure to invest in a sports bra that will accommodate increased cleavage while preventing painful bouncing.
6. Listen to your instincts.
If something feels odd or wrong, stop doing it. Perfecting the curtsey lunge or chest press can come later in life””for now, take care of yourself and your baby, and use your workouts as a chance to relax, unwind and prepare your body for the incredible feats of childhood and motherhood!
Jorie Mark is Vitacost.com’s Director of Marketing Communications and mother to three children, ages 3 to 10.