Had a miscarriage in 2010 and ttc ever since my periods average about ever 40 days im having a 21 blood test check ovulation?

Ovulation. 40 day cycles may signify the lack of appropriate ovulation. Checking Progesterone on day 21 in a 40 day cycle may also not provide you with accurate information as you may be ovulating later in the cycle. You should see your gynecologist or a fertility specialst for an evaluation and possible treatment for ovulation.