Why does pelvic girdle pain cause back pain in pregnancy?

The pelvic girdle includes the joints at the front and back of the pelvis. During pregnancy, changing weight distribution, abdominal growth, and movement patterns can place more demand on these joints. The sacroiliac joints connect the pelvis with the lower spine, so pain from this region may be felt across the buttocks, hips, groin, or lower back. Muscles around the abdomen, pelvis, and spine may tighten to provide extra support, creating aching or fatigue.

Symptoms often flare with stairs, turning in bed, standing on one leg, getting out of a car, or walking unevenly. Back pain in pregnancy has other causes too, so a clinician should consider the full pattern and your pregnancy stage.

Change position regularly and keep movements symmetrical where possible. Sit down to dress, take smaller steps on stairs, and place a pillow between your knees when side-lying. Avoid carrying a child on one hip and ask for help with heavy or uneven loads. A maternity physiotherapist can assess your movement and suggest pelvic stability exercises, supportive equipment, or activity adjustments. Gentle movement is often more helpful than prolonged bed rest, but stop an activity that sharply increases pain.

Tell your maternity team about pain that limits walking, sleep, work, or daily tasks, especially if it is getting worse. Seek urgent assessment for back pain with vaginal bleeding, fluid loss, regular tightening, fever, painful urination, severe abdominal pain, leg weakness, or numbness around the genitals. New loss of bladder or bowel control also needs prompt attention.

Does my pain pattern fit pelvic girdle pain, or should we check another cause? Would physiotherapy or a support belt be suitable? Which movements should I modify, and what symptoms mean I should contact the maternity team immediately?