Hi flump, just seen your message. I had DD2 6 weeks ago. I had SPD from the 12th week of my pregancy and from 22 weeks I was in a wheelchair the SPD was so bad. So I can completely understand where you are coming from with wanting it to be over, and I have a 4 year old that it has been very hard on.
Did you have SPD with your previous pregnancies?
I spoke to my OB about having the baby early too (either induction or c/s), but all advice was that 39 weeks with no other medical indictations was the best for the baby. If you induce the baby too early then you are running the risk of respitory problems, even at 37 weeks, because the baby is simply not ready its you that has had enough! In the end I was booked in for an induction at 39 weeks but my DD2 came at 38 weeks, 2 days. It was a very quick (early) labour, mainly because my symphisis pubis had been ready to go for so long. As the ligaments were so soft I didn't do any pushing, basically she fell out and early because my body just kinda gave up!
The other thing to remember about any sort of induction is that it increases your chances of needing intervention such as forceps/ventouse or c/s. This is the worst thing that could happen for your SPD as with a forceps/ventouse you would be in the lithomy position and hip abduction would only aggrevate your condition and perhaps take you longer to get over after the birth.
I'm 6 weeks on and am now able to go out on crutches (though not for too long, long journeys I still need the wheelchair) so it does get better very quickly, as before the birth I was unable to walk at all.
I did eat a lot of pineapple (meant to make cervix softer). If you can hang on to 39 weeks perhaps you would have an understanding OB if you were desperate to induce or c/s by then.
You should talk to them as they may well have had some experience with SPD and can help you deliver earlier then 40 weeks if you really feel that the extra couple of weeks is too hard. But I have to say my OB didn't suggest it, I had to and I was armed with LOADS of research and it took 45 minutes to negotiate as I wanted to be induced at 38 weeks, his ideal is spontaneous labour and in the end we agreed on 39.
None of it was needed anyway!!
Are you in touch with the Pelvis Partnership at all?
Hope this has helped though, you aren't alone