Obstetrician Richard Bloy says that how much weight you should gain during pregnancy really depends on your weight before you were pregnant. If you're normal weight, then 25 to 35 pounds is good. If you're underweight, up to 40 pounds might be appropriate. Gaining steady is the key. "Basically in the first 3rd of the pregnancy the women gain maybe about 2 pounds a month, the 2nd 3rd about 3 pounds a month, and in the last 3rd of the pregnancy, about a pound a week."

Unfortunately expectant mothers need to watch their diets pretty closely. Expectant mother Saundra Best says, "Stay away from the fast food and try to limit your high carbs after dinner, try to taper them off, that's worked really well for me. You can maintain a healthy life and healthy pregnancy and still be active."

Dr. Bloy also says that obviously a little alteration of the way you exercise may be necessary. But staying active is important, because you may be eating for two now- but eventually you'll want that weight to come off. "Right at birth a woman's going to lose a good solid 10 to maybe 12 or even 15 pounds of water and baby and placenta. And then over the next 6 weeks many women will lose as much as all of the weight up to the last 10 pounds, those last 10 pounds are a little tough."

But experts say you take 9 months putting the weight on so give yourself 9 months to take it off.

It is never safe to lose weight during pregnancy -- both you and your baby need the proper nutrients in order to be healthy.