Why do I feel like I'm waddling?

As you get closer to your due date, the cartilage and ligaments that join your pelvic bones increasingly soften and relax, causing an expansion that allows your baby to pass through the birth canal more easily. These changes cause some pregnant women to waddle, says Carolyn Sampselle, a professor of nursing at the University of Michigan. Lightening, when your baby descends lower into your pelvis prior to birth, can also cause the telltale waddle. Some women experience lightening several weeks before their babies arrive.