Speaking as a patient, I suffered with this during pregnancy. It was excruciating. I was eventually diagnosed with hypermobile Ehlers Danlos Syndrome and now have to use a wheelchair. Many women with this type of EDS suffer with pubic symphysis dysfunction as pregnancy hormones make the joints even looser than they are anyway.
Perhaps something to consider on discovery, as EDS is little known and very under-diagnosed. Early diagnosis can mean better outcomes for the individual. It is also genetic.
Another potential consideration is Ehlers Danlos Syndrome http://www.ehlers-danlos.org