Pregnancy is a time of tremendous change for the female body. Some of those changes can come with a bit of discomfort. There will be changes to your skin, breasts, muscles, uterus (a very large muscle), pelvis, digestive system, circulatory system, weight, genital area, and your sleep patterns, just to name a few. Women feel these aches and pains due to a hormone called relaxin which causes the ligaments to relax in preparation for delivery.