Constipation is a common problem for pregnant women in the initial stages of the pregnancy. The most common reason for the problem is the change in the hormonal levels. During the first trimester of pregnancy there is an increase in the progesterone hormones, which slows down the movement of food through the digestive tract. As the muscles in the wall of the bowel relaxes, it becomes difficult to move the food and eliminate the waste. Later on, as the uterus starts to swell and push against the stomach and other organs as it grows, the problem of constipation can persist.