Relaxation of which of these joints in pregnancy can cause waddling gait?

The joint between the two pubic bones is the pubic symphysis. It is not a stable joint. They have limited motion but do become more mobile and even separate a bit during pregnancy. The relaxation is attributed to the hormone relaxin. This is a pa of maternal adaptation for accomodation of the fetus in the pelvis during childbih There may also be separation of symphysis pubis or one of the sacroiliac synchondrosis during labour, that may lead to pain and marked difficulty in locomotion. The pain usually subsides after few days of delivery, However if it remains symptomatic, may be treated with bed rest, analgesics and pelvic binder.