My 18 Yr Old Daughter Period Has Been On For

My 18 yr old daughter period has been on for a month and a half none stop. However I took her to the obgyn, he prescribed medroxyprogesterone and ordered lab work. In addition she had a sonogram taken, pregnancy has been ruled out. She has a follow up on Friday of this week which now her period has been on for 2 months. I'm wondering if she has pcos, I asked her doctor but no response from him yet. Any suggestions of what's causing her issue?????