There is a place in Dracut called New Beginnings by JoLynn, I know they offer it. I was going to check them out but haven't had time yet. Also, I don't know where exactly you are, but Lowell General Hospital had something in a brochure I saw recently.
Re: Merrimack Valley-Southern NH Prenatal Yoga
The Yoga Tree in Haverhill!
https://www.theyogatreestudio.com/