I work with a woman who calls in at least 1 time a week. Should she be canned?

I knew yesterday this girl was going to call in. Last week she missed 2 days because she said she had pink eye. She is about 7 months pregnant and called in over and over the 1st 3 months of her pregnancy because of one thing or another. I am not kidding when I say she has probably called in at least 10 or 12 times in the last 2 months. Why do they put up with this? I get tired of the calls at 5 am asking me to come into work on my days off. We nurse in a hospital and I have told them not to call me at home anymore to fill in for this girl. I refuse to work for her. If it was 2 or 3 calls in a couple months, I would understand, but not day after day. Is there a law about terminating someone who is pregnant in Illinois?