New job

So I started a new job on August 12th and I’m currently 24 weeks pregnant. I interviewed and got the job at 17 weeks pregnant but between the hiring process and orientation dates they offer is why I began on the 12th. While working I began swelling really bad and my OB wanted to put some restrictions on me for work since I had preeclampsia with my last pregnancy. I informed my HR manager and she told me I wasn’t allowed to return to work until the restrictions were sent to her by my OB. Later that evening after I told her what was going on she called me and tried to convince me to resign....my question is can they force me to resign or fire me?