What should I do?

So this is my second pregnancy the first one ended in a MC and I have an OB and we did some bloodwork and an early ultrasound and we saw baby’s heartbeat at 6 weeks 4 days. My progesterone is pretty low but he doesn’t believe in supplemental progesterone so I went to see a new OB yesterday to get her opinion because I know how important progesterone is in pregnancy and she said she’ll put my on progesterone supplements. Why do doctors say two different things ? Do I need the supplement or do I not