Can my job let me go once I give them my notice?

So I feel like a crappy  person doing this to my job, but I come back from. Maternity leave on Monday. I've only been gone six weeks. Well this week my husband I decided we will be moving half way across the United States at the beginning of next month. I will be giving work my notice once I go back. Legally can they let me go early? I have a feeling they are going to be pissed I've been gone for 6 weeks and then am quitting once I get back. I need to continue working until we leave though for insurance purposes considering I have a 5 week old.