Fertility & hormones
Progesterone blood test
A progesterone blood test measures the hormone that rises after ovulation to prepare the womb lining for a possible pregnancy. Timed to the second half of the cycle (around day 21 of a 28-day cycle), it's the standard way to confirm that ovulation has taken place.
- What it measures
- Progesterone, the hormone that confirms ovulation
- Sample
- Venous blood sample
- Fasting
- Not required (timing in your cycle matters, see note)
- Also known as
- day-21 progesterone
- Included in 57 Health tests
- 2 panels, from £110
Progesterone reference range
Guide only| Category | Guide range |
|---|---|
| Mid-luteal (≈ day 21), ovulatory | > 30 nmol/L |
Progesterone is only meaningful when timed to your cycle. A mid-luteal sample (about 7 days before your next period, around day 21 of a 28-day cycle) above roughly 30 nmol/L supports that ovulation occurred. It is naturally low in the first half of the cycle and after menopause. Ranges vary by laboratory.
These are general UK adult guide ranges from public health sources, shown for orientation only. Reference ranges vary by laboratory, assay, age and sex, so your result is always interpreted against the range quoted by the analysing laboratory on your report.
What does a high progesterone level mean?
A raised progesterone in the second half of the cycle is the expected, reassuring finding, and shows that ovulation has occurred.
It also rises in pregnancy. Outside these contexts, a high result is uncommon and interpreted alongside your cycle and other hormones.
What does a low progesterone level mean?
A low mid-luteal progesterone suggests ovulation may not have occurred in that cycle, which can be relevant to fertility, though a single low result can also mean the test was mistimed.
It's interpreted alongside your cycle length and timing, and often repeated or combined with other tests before drawing conclusions.
When to consider a progesterone test
- Confirming ovulation when trying to conceive
- Irregular cycles alongside fertility questions
- Investigating unexplained infertility
- As part of a wider fertility hormone panel
Frequently asked questions
This page is general information about a blood marker and is not medical advice or a diagnosis. A progesterone test screens and gives context; results are interpreted by a clinician alongside your symptoms, history and other markers. Always follow the guidance on your own report.