Hiya Duffster, There is no quick fix but your wife should start cantienica yoga which is extremely helpful not just during pregnancy but particularly during delivery and afterwards, to get the pelvic area sorted again.
I wouldn't go to an osteopath or chiropractor because it's too much outside influence - never good in pregnancy.
I just tried google-ing it but there are not British pages coming up but a few vids on YouTube. Have a look. If you're unlucky, drop a message and I'll try and get a book with lots of pics to you in the post asap.
Hope your wife gets better fast!
Just thought of something else - buy a babybelt (hope you can get them in England), it supports the pelvis. Also - drinking more than usual also helps. Above all - not doing too much, not carrying anything at all, if possible, and doing gentle exercises to get it all sorted.
Here's a alink for a babybelt: