This is a tough decision. I read this article yesterday and while it doesn’t exactly fit your situation, I think it makes some excellent points about the realities of women who come and go from the workplace.
The Downside of Opting Out - Page 3 - The Daily Beast
Good luck with whatever you decide to do. Hopefully you can find something that is rewarding for you and will still be flexible for the time when you match and have a newborn.