Hello Josephron welcome welcome [IMG=http://www.singaporemotherhood.com/forumboard/clipart/happy.gif]
Here are the info I found online,
Progesterone levels vary considerably from cycle to cycle and woman to woman, both non-pregnant and pregnant. So the levels can only be averages and they change with the timing of the cycle. In general, the midluteal (middle of the second half of the cycle) progesterone in a non-pregnant patient is 8 to 10, but can be as high as 20 ng/ml. In a pregnancy cycle, it should be greater than 10 to 12 ng/ml to have a better chance of a good pregnancy outcome, but in general, we like to see 16 or over.
Everyone you ask will have slightly different numbers. Also there are differences as to what to do if the levels are low, with some docs giving progesterone (pills, shots, suppositories) and others not treating unless there has been some proof of a preexisting low progesterone in non-pregnancy cycles.
Overall, the levels you had were in the normal range both in the non-pregnant and pregnant cycles. Whether additional progesterone might have helped would just be a guess, but one you will have to decide prior to the next pregnancy. If you are going to try to raise the progesterone levels, you will need to start as soon as you know you are pregnant.