That would probably be a good idea. The sacroiliac (SI) joint is where the pelvis meets the bottom part of the spine. Pain in the SI joint is common in the last trimester of pregnancy. At this time, your body produces a hormone called relaxin that helps loosen ligaments of the pelvis. This helps the baby fit through the birth canal. The problem is, relaxin makes all the ligaments in your body looser, putting them at risk for injuries. If you strained your hips while your joints were affected by relaxin, you might have stretched the SI ligaments too far.
Your doctor will have some recommendations for ways to get rid of the pain. You might need to work with a physical or occupational therapist. A therapist can help you manage the pain and design an exercise program that will strengthen your SI joint.