I did - from around 20 weeks I think it was. I'd been to a chiro years before that but had a long break in between. I went because I was having sciatica trouble and it was pretty much gone within a few weeks, then kept going for the rest of my pregnancy (and continue to now) I went weekly for a few weeks, then fortnightly, then weekly again over the last month.

I do really think it helped with birth too, I can't explain how, but I just felt so good throughout my pregnancy and birth and I think the chiro helped. I laid on a special hollowed out pillow for my tummy so never felt any discomfort, just not very graceful getting on and off the table towards the end there!

Normally they would take x-rays etc before beginning treatment but they won't be able to do that with you already being pregnant, my recommendation would be to ask around and find a chiro really experienced with pregnant mothers. Good luck and hope it helps if that's what you choose to do