For our great grandmothers, being pregnant was viewed as a fragile condition and exercise was thus discouraged. This is no longer true as studies now show that fitness in moderation can make for a healthier birth and reduce the risk of a pre-term delivery. Of course, there are still certain precautions you should take and exercises you should avoid.

And you need to ensure sure you're getting enough food and calories if you're burning them off. You should also avoid twisting, bouncing, jerking or anything high impact. Lying on your back doing sit ups for example, is also discouraged as it can put stress on your organs. President and owner of Toronto's Yorkville Clubs, Mark Kehr, shares his advice on exercise and pregnancy.

Q: Should you be exercising if you're pregnant?

A: You shouldn't be doing anything until after three months because you don't want to overexert and you don't want to cause a miscarriage. Check with your doctor before you embark on any fitness program (see when not to exercise).

Q: What are some safe exercises for pregnant women?

A: If you have the green light from your doctor to go ahead, what's great for pregnant women is yoga, stretching and resistance exercise (click for tips on doing these exercises safely). Light-weight resistance exercises really help your back, your legs and your glute muscles. These areas are what get really tired during pregnancy. I've trained a lot of women right to delivery. Exercise really helps for an easier delivery most of the time and a very quick recovery.

Q: What about heart rate? I've heard that your heart rate shouldn't go too high or else the baby could overheat. Do you know anything about this?

A: It really shouldn't go more than 123 to 140 beats per minute.

Q: Apparently, pregnant women should be mindful that they don't hold their breath and that they make sure they breathe with each movement. What do you advise for breathing properly?

A: With anyone who's exercising, you should be breathing out when you exert the most. It's very important that you do this with every repetition especially with women that are pregnant.

Q: They also say you shouldn't start a new exercise program but rather to continue on with your normal regiment. Is this true throughout pregnancy or just in the first trimester?

A: I think unless your doctor advises differently, it's very safe for somebody after three months to begin an exercise program that's monitored and safe. Even if you haven't exercised before and you're over that three month term, it's definitely safe to embark on a new fitness program if your doctor approves.

Q: How much more water should you be chugging back when you're drinking for two?

A: If you're working out you should have at least two to three glasses.

Q: Anything you shouldn't be doing?

A: Nothing that's going to make you strain too much. You don't want to have to hold your breath and really strain in an exercise. If you think you're overdoing it, there's a very good chance you are. Listen to your body, your body will tell you (see body signs of danger).

Q: How about squats? I heard they can be an issue especially in the last trimester.

A: Each pregnancy is different so it's got to be tailored to individuals. One of the women I was training was a competitive body builder and she was doing leg presses and squats in her ninth month of pregnancy.

Q: Obviously, the goals for pregnant women are going to be different especially when it comes to weight gain. What sorts of fitness goals might a pregnant woman strive for?

A: It's general firming and toning. You want to be able to bounce back from your delivery and your pregnancy. Ladies want to get their body back. Some women use the excuse, I had kids six years ago and that's why I'm out of shape.

Q: It's tempting to use pregnancy as an excuse to indulge because you're going to be gaining 20 pounds regardless. Although, this could be a dangerous assumption because of course you want to be at your healthiest when you're carrying.

A: It's true and then these women are overweight for the rest of their lives. You have to step up to the plate.

*This interview has been edited and condensed