When you’re pregnant, food goes through your digestive system at a slower pace. As food slows down, more water is absorbed into your body, which makes your stool harder and more difficult to pass. The iron in your prenatal vitamins can also make you constipated. Drinking more water, exercising, and eating more fiber may help. If constipation becomes a problem, ask your healthcare team to recommend a safe laxative or stool softener.