While starting a new tough fitness regime during pregnancy isn't a good idea, it is OK to get some exercise. That is not to say that if you are in great shape and work out regularly that you should not continue, but someone who rarely does any exercise should take it extra easy.

Staying fit during pregnancy can help with delivery, reduce the risk of complications during labor, and speed up your recovery time.

Mild to moderate exercise can also reduce your risk of high blood pressure during pregnancy, gestational diabetes, leg cramps, constipation, varicose veins, swelled ankles, and hemorrhoids.

Women who worked out while pregnant also claim they experienced better self esteem and confidence, and had an over all better feeling about their new shape. They also reported fewer feelings of depression, and fewer mood swings. Exercise can also give you more energy, something most women are lacking during pregnancy, and help you sleep better. 97% of women can't sleep through the night by the end of their pregnancy.

It's also good for your baby. The offspring of women who worked out rated higher on overall intelligence and language skills, and showed this off at as young as 5 days old, and this trend continued on until their 5 year check up!

Good work outs to do while pregnant are yoga (routines designed for pregnant women), swimming, walking, mild to moderate weight training, and biking. All of these exercises are easy on your joints, and wont bounce the baby around too much.

There are certain things that you shouldn't do while you're pregnant too. Obviously playing rough sports like basketball, soccer, etc are dangerous to your growing baby, and you should stay on the sidelines.

After the first trimester you should avoid exercises that require you to lay flat on your back, as this inhibits blood supply to the baby.

Stop when you feel fatigued, and don't go until you're exhausted, you have less oxygen when you are pregnant so you won't be able to do things you normally can.

Don't do anything that you might lose your balance doing, this could cause serious trauma to your baby.

You need extra calories when you are pregnant, and you will need even more if you are exercising.

Drink lots of water, work out in a cool place, and don't let yourself get too hot.

You should check with your doctor about how high your heart rate can go so that you don't over exert yourself.