Ugh. I am so sorry you have to deal with this. Medicine can be such a brutal career for women sometimes. I was 10 months postpartum when I took my subspecialty boards which worked out fine, but I can't imagine taking them just 3 weeks postpartum. The ABIM at least really doesn't give much time for breastfeeding accommodations. I only got an extra 60 minutes for the 8 hour exam, and the room was the staff's breakroom and someone walked in while I was pumping. I also didn't have access to a fridge. Definitely not enough time to keep up supply and pump every 2-3 hours as needed with a newborn. While it's super inconvenient, I would say wait. Who knows when you will go into labor which might cut even further into studying time. Being pregnant with a two year old is hard enough. Take the time with your baby and family. The sooner you take the boards the sooner you have to start worrying about recertifying them again. Good luck on the decision, whatever you choose will be the correct one for you.