Low Progesterone Advice

K
Hi ladies,
My blood draw results are back and the hcg levels are doubling, which is a huge relief. But I'm concerned about my progesterone which is 15.38 at exactly 5 weeks. My doc says that's fine, and I don't need supplements, but she is happy to prescribe it if it makes me feel better. 
During my previous MC (blighted ovum) levels only got to 16.7 at 8 weeks. Clearly my progesterone tends to be on the lower side. Would you take progesterone sups if you were in my shoes or not? Are there any women who have levels around 15 and DID NOT supplement but still had a healthy pregnancies? 
Thanks for any advice!