Oncology nurses weigh in

I work on a small pediatric hem onc floor, we have 16 beds about 27 nurses. Many of the nurses are pregnant right now. We do the best we can with assignments to not give the pregnant nurses chemo heavy assignments or patients that are contagious. We can’t always guarantee it though. One of the nurses asked our boss to ensure she wouldn’t get chemo patients. Our boss essentially told her that she is shit out of luck and to deal with it. How do your floors deal with situations like this?