Weight gain is important during pregnancy. However, how you gain
the weight is the most important. Slow and steady growth, of one to
two pounds per week is safest for you and the baby in the middle
trimester. The weight gain should slow during the end. When the
weight gain is rapid, the skin doesn’t have a chance to stretch
naturally. Stretch marks occur from skin that is pulled too tight too
quickly. If you can moderate your diet and exercise, it will go a long
way to helping control any stretch mark outbreaks.