So, if we have a look at the anatomy, we have three joints in our pelvis, one at the front - the pubic synthesis, and two at the back - the sacroiliac joints. When any two of these joints become dysfunctional and cause pain, if at the front it’s called SPD and if at the back, it’s called PGP. Basically, these two are very similar, but pelvic girdle pain is generally in the back.
The reason pain can happen during pregnancy, is that a super clever hormone called relaxin is released in your system, encouraging your ligaments to start to loosen up in preparation for labour. Your joints, which aren’t designed to move a great deal, suddenly become a lot more mobile. Having a less stable frame but more weight to try and manage is a real recipe for disaster.You would think that having a really sturdy frame to carry the extra weight would be the best option, but if it wasn’t for the laxity in your ligaments it would be really difficult to deliver naturally. There just wouldn’t be the space for a baby to come through as easily.