A pregnant client at 28 weeks gestation is observed walking with a waddling gait. The nurse explains that this change in walking is a normal part of pregnancy. Which of the following factors is most likely contributing to the client's waddling gait?

A. Development of scoliosis in the spine: Scoliosis is a lateral curvature of the spine and is not a typical change during pregnancy. Pregnancy usually leads to lumbar lordosis, not scoliosis. This spinal shift affects posture but is not responsible for a waddling gait in pregnancy. B. Increased blood volume leading to leg swelling: While increased blood volume can cause leg swelling and discomfort, it does not significantly alter the mechanics of walking. Edema may cause heaviness but not the joint instability seen with a waddling gait. C. Relaxation of pelvic ligaments and joints: Pregnancy hormones like relaxin cause pelvic ligaments and joints to loosen in preparation for childbirth. This increased mobility alters pelvic alignment and stability, leading to the characteristic waddling gait. D. Increased muscle strength in the lower extremities: Muscle strength typically does not increase during pregnancy; fatigue and reduced endurance are more common. Stronger muscles would improve balance, not cause a waddling gait, making this an unlikely factor.