I saw an osteo and a massage therapist throughout my pregnancy.

I had pelvis, hip and lower back pain. I had a bit of drama with my SI joints too. I found both the osteo and massage really helpful.

There are awsome chiros and there are also crap ones, same goes for physio, osteo and massage. Whatever you choose, you need to find a good one, who is experienced in treating pregnant women.

FWIW- If it took 18 months to fix your last problem i would not be going back. If you don't get positive results with a few treatments i would try something else. JMO of course!