Unfortunately, yes. Throughout your pregnancy, hormonal changes can result in sluggish digestion. Then as your uterus grows, it compounds the problem by putting more pressure on your intestines and rectum.
To understand the problem, it helps to know how your digestive system works. As food moves through the colon, muscle contractions push it along while water is absorbed, creating a semi-solid waste. If the colon absorbs too much water or if the muscle contractions are too slow, the result is the hard, dry stools characteristic of constipation. So the key is to keep things moving.