Should I tell my boss I’m trying for a baby?

I work in a lab where we work with hazardous chemicals. The last lady that was working here and was pregnant got sent to work a desk job while she was pregnant. Should I tell my boss I’m interested in getting pregnant? I don’t plan on quitting because I need the income to pay bills. I’ve been delaying pregnancy for so long because I’m scared for my job. Any advise on how to navigate this process.