A progesterone blood test can help confirm whether ovulation has recently occurred. However, “day 21” is not the right timing for everyone.

When should you test?
Testing is usually done about seven days before your expected period. For a 28-day cycle, this is around day 21; for a 35-day cycle, around day 28. Irregular cycles may require individualized timing.

What do the results mean?
An appropriately timed progesterone level above 3 ng/mL (about 9.5 nmol/L) provides evidence of recent ovulation. This is not a target for pregnancy success. Laboratory reference ranges vary.

Does a low result mean no ovulation?
Not necessarily. Testing too early or too late can produce a low result. Your healthcare provider may recommend repeating the test with better timing.

Can it diagnose low progesterone?
Progesterone fluctuates throughout the day. One result cannot reliably assess luteal-phase quality, measure egg quality or predict pregnancy.

If you take progesterone or fertility medication, tell your provider because this affects interpretation.

At Longevity Fertility Centre, we review your cycle history and fertility results as part of an individualized assessment.

Calgary & Edmonton