Progesterone (ovulatory test)

Mid-luteal cycle progesterone - serum progesterone is tested one week before a period is expected (on day 21 of a 28 day menstrual cycle).

The level of progesterone that indicates ovulation is variable. NICE suggest that "..values range from 16 to 28 nmol/l as the lowest limit indicative of ovulation..." (1).

For assessment of ovulation for women with a regular menstrual cycle (2)

• Measure mid-luteal phase progesterone (e.g day 21 of 28 day cycle; day 28 of 35 day cycle):
  • sample should be taken 7 days before the expected period and interpreted when the next period has begun
  • >30 nmol/L is consistent with ovulation and no further biochemical assessment is indicated
  • 10-30 nmol/L may require repeat with review of cycle timing
  • <30 nmol/L (confirmed) requires further investigation as below for anovulation/oligo-ovulation

This is the most commonly used method.

Reference:

• NICE (February 2013). Fertility Assessment and treatment for people with fertility problems
• East Kent Hospitals NHS Foundation Trust (Accessed 29/6/15). Subfertility - Biochemical Assessment and Initial Investigations.