Progesterone Supplements

Hi ladies! So I've recently become pregnant again after my mmc and D&C; on February 22nd. When I had bloodwork done for that pregnancy, my progesterone came back just slightly low, but they ordered me supplements just in case. I found out I was having a mmc 2 days later, so I still have the pills. That pregnancy was lost as a result of a chromosomal abnormality though, not because of low progesterone. So my question is, should I just start taking those right away for this pregnancy? The OB is having me get bloodwork done next week and wants me to wait until then to see if I actually need it, but I'm worried I could lose the baby within the next week if I do need it. Would it hurt to take it if I don't need it?