Should I ask to continue?

My doctor put me on 200 mg progesterone at almost 8 weeks. I had blood tests at week 6 and the had thought they had already started me on it but they hadn't. All she told me is that my levels are on the lower side so it will help prevent a miscarriage during my first trimester. I am on my second and last refil and I am currently 15 weeks. Baby seems to be doing great and I am not feeling as crappy as I did during the first tri. I go in for my next appointment on sept 8 and I am wondering if I should ask to continue taking the progesterone. I know the placenta has supposedly taken over hormone production. Can anyone tell me any benefits to continuing progesterone into the second tri or any reasons to stop? Thank you.