I asked my miracle massage therapist -- based here in Kansas City -- what he thought of your description, and he wrote the following:
"I haven't heard the exact terminology being used, but I do understand the process. The hormones produced during pregnancy actually soften the ligaments (not the muscles) in the joints througout the body. The end purpose of this being to have a pelvic girdle which is flexible enought to adapt to the passage of a 10-lb object through a 10-oz hole at birth. Immediately after birth the hormones go away and the ligaments stiffen back up to normal tension in a few weeks. It is possible that the SI (sacro-iliac) joints in the pelvis could reset at an awkward angle, causing the discomfort described. From her activity description I have a feeling that her hip flexor muscles are too tight, causing pressure and discomfort in the lower back and pelvic area. It is my prejudice, or course, but I would start with some massage which focused on the hip flexors and pelvic area in general, combined with stretching. This would be the least invasive, and relatively cheap to start with. She could move up the treatment food chain if that did not work."
Otis is the best ... he has helped me through two pregnancies, before, during and after. Let me know if you want to see him.