Any recommendations on how to handle this is appreciated.

I'm personally ready for maternity leave. I work in a hospital and do 12.5 hour days.

My bosses want me to work up until two days before my due date because we have myself and 3 other girls all due within 2 months apart. (So right now a couple are gone already)

I've mentioned it to them that I wanted to start it mid-February or the beginning of March, but they just brushed it away.

I decided to try to just try to do it and help them out with not being short staffed.

Its just too much for me. My body ACHES at the end of the day and I feel horrible for the next 2 days after I work.

Any ideas on how to say something to them about needing to start it? I just dont want to come off the wrong way.