2. Get enough calories


Exercise burns calories, so be sure to eat well to nourish and strengthen your body. When you're pregnant, you naturally gain weight as your baby grows. The amount you need to gain varies based on your pre-pregnancy weight.
If your body mass index (BMI) is in a healthy range (between 18.5 and 24.9), you'll need to eat about 340 more calories a day in the second trimester than before you were pregnant and about 450 more calories a day in the third trimester – and possibly more than that depending on your exercise routine. If you're underweight or overweight, you may need to gain a little more or less than someone with a healthy BMI and adjust your calorie intake accordingly.
Your doctor will monitor your weight as your pregnancy progresses and can help you keep your weight gain on track.

3. Skip dangerous sports


Avoid sports that involve lots of contact (like basketball and soccer) as well as activities that might throw you off balance and cause a fall, such as horseback riding, surfing, water skiing, gymnastics, downhill skiing, or mountain biking. Cycling early in your pregnancy should be okay if you're already comfortable on a bike, but it's probably best to stick to stationary bikes later in pregnancy.
Avoid racquet sports if you never played them before getting pregnant because the rapid movements and sudden changes in direction could affect your balance and make you fall.
All pregnant women should avoid scuba diving – babies in the womb aren't protected from the effects of pressure changes and may not develop normally as a result.

4. Wear the right clothes


Wear loose-fitting, breathable clothing. Dress in layers so it's easy to peel off a layer or two after you've warmed up or if you get overheated. Make sure your maternity bra is supportive enough, and choose athletic shoes that fit properly.
If your shoe size has changed because of mild swelling, stash away your pre-pregnancy sneakers and buy a new pair. You may want to swap out the liners they came with for gel liners that provide better shock absorption.

5. Warm up


Warming up prepares your muscles and joints for exercise and increases your heart rate slowly. If you skip the warm-up and jump into strenuous activity before your body is ready, you could strain your muscles and ligaments and have more aches and pains after your workout.
A good way to warm up is to start your chosen activity at a low intensity and slowly increase it during the first five to eight minutes. This prepares the muscles you'll be using for more vigorous movement. For example, if your workout is walking, go slowly for the first few minutes and gradually pick up the pace.

6. Drink plenty of water


Drink water before, during, and after exercising. Otherwise you can become dehydrated, which can set off a chain of events that leads to a reduced of amount of blood reaching the placenta. Dehydration can also increase your risk of overheating or even trigger contractions.
There's no official recommendation for how much water pregnant women should drink while exercising, but many experts recommend a simple technique to gauge whether you're drinking enough: Check the color of your urine. Dark yellow urine is a sign of dehydration. If that's the case for you, have one or two glasses of water every hour until your urine is pale yellow or nearly clear.

7. Don't lie flat on your back


After the first trimester, avoid exercising while lying flat on your back. The weight of your uterus puts pressure on a major vein called the vena cava, which can reduce blood flow to your heart and may diminish blood flow to your brain and uterus. This can make you dizzy, short of breath, or nauseated.
Some women are comfortable in this position well into their pregnancies, but this isn't necessarily a good indication of whether blood flow to your uterus is affected. Putting pillows or a foam wedge behind your back to prop up your upper body while you exercise enables you to be almost flat on your back without compressing the vena cava.

8. Keep moving


Remaining motionless or standing in one place for prolonged periods – when you're lifting weights or doing yoga poses, for example – can reduce blood flow to your heart and uterus and cause blood to pool in your legs, lowering your blood pressure and making you dizzy. Keep moving by switching positions or walking in place.

9. Don't overdo it


Don't exercise until you're exhausted. Slow down if you can't carry on a conversation comfortably. In general, the best guideline is to listen to your body. Always stop if something hurts.
You should feel like you're working your body, not punishing it. If you feel completely drained instead of invigorated after a workout, you're probably overdoing it.
After exercising, try to rest for an equivalent amount of time before getting on with your day. For example, if you've just jogged for 30 minutes, rest quietly for 30 minutes.
To be extra safe, read our signs of danger during pregnancy exercise.

10. Don't exercise in high heat or humidity


Increased blood flow and a higher metabolic rate when you're pregnant mean you'll feel warmer than usual, especially when you exercise. As a result, you may get overheated much faster than you normally would, even before your belly is big. That's why it's especially important to avoid exercising in hot or humid conditions during pregnancy. When it's hot out, your body has a harder time regulating your body temperature.
Signs of being overheated are largely individual, but pay attention if you're sweating a lot or feel uncomfortably warm, nauseated, dizzy, or short of breath.
To cool off quickly, stop exercising, take off layers, and change your environment: Go someplace with air-conditioning or step into a cool shower. Hydrating is also key, so drink lots of water.
Note: Avoid activities such as doing Bikram yoga or "hot Pilates" and lounging in saunas or hot tubs. These activities can raise your core temperature to unsafe levels because your body can't disperse heat effectively in a hot environment.

11. Get up from the floor slowly


Your center of gravity shifts as your belly grows, so it's important to take extra care when you change positions. Getting up too quickly can make you dizzy and may cause you to lose your footing and fall.

12. Cool down


At the end of your workout, walk in place for five to 10 minutes and do some pregnancy-friendly stretching. This improves your flexibility while getting your heart rate back to normal. Stretching also prevents sore muscles.

13. Make it a habit


Make a commitment to exercise regularly. Keeping up a routine is easier on your body than long periods of inertia interrupted by spurts of activity. According to the American College of Obstetricians and Gynecologists, you can safely do 20 to 30 minutes of moderate exercise on most or all days of the week as long as you have the go-ahead from your healthcare provider.
One of the best ways to stick to a workout routine is to invite a buddy to meet you for walks, runs, exercise classes, or gym time. You'll be more motivated to show up, and you'll get quality time with your friend while doing something important for your health and pregnancy.