When to take progesterone test if i have 35 day cycle?

35 day cycle: A 35 day cycle if regular is not abnormal. Ovulation occurs on day 21 in such cycles. Peak progesterone will occur on day 22-24 but test for it on day 28-29, and if low at that point, this may cause a miscarriage. Most times it will be normal all the way from day 22 to day 33-34 in a 35 day cycle. Pregnancy is most likely at day 22-24. See an infertility provider if attempting pregnancy.