Oestrogens . Patient guide
Progesterone Blood Test
What is Progesterone
Progesterone is the hormone released by the ovary after ovulation. A well-timed progesterone test is the standard way to confirm that ovulation has occurred, which is why it is central to fertility investigations.
This biomarker entry is being clinically reviewed by our team. The factual content draws on UK guidance (NICE, NHS, Royal Colleges and the relevant speciality society where cited).
Reference range
Reported in nmol/L. Final reports always carry the issuing laboratory's range, which is what your clinician will interpret against.
| Group | Range | Note |
|---|---|---|
| Mid-luteal (about 7 days before the next period) | over 30 suggests ovulation | nmol/L; timing to the individual cycle is critical |
| Follicular phase (before ovulation) | low (under 5) | nmol/L |
What it is
After an egg is released, the remaining follicle (the corpus luteum) produces progesterone, which prepares the womb lining for a possible pregnancy. Levels are very low before ovulation and peak about a week after, so timing the test to the cycle is essential.
Why a clinician would order it
Progesterone is measured mainly to confirm ovulation in women trying to conceive (the "day 21", or mid-luteal, test), to investigate irregular cycles, and in early pregnancy assessment. In men and non-cycling contexts it has limited routine use.
If your level is outside the range
Symptoms of low Progesterone
- Irregular cycles
- Difficulty conceiving
- Spotting before periods
What low can indicate. A mid-luteal level that is low can indicate that ovulation did not occur that cycle, or that the test was mistimed relative to your actual ovulation. The test is often repeated with careful cycle timing.
Symptoms of high Progesterone
- Raised levels are expected in the luteal phase and in pregnancy rather than being a problem
What high can indicate. A high mid-luteal progesterone confirms ovulation. Progesterone is also high in pregnancy.
Testing tips
Timing is everything: the sample should be taken about 7 days before the next expected period (adjusted for your own cycle length), not simply on "day 21", which only applies to a 28-day cycle. A morning sample is preferred.
Sources
UK guidance our clinicians use when interpreting this marker.
This page is general patient information, not personal medical advice. A GMC-registered clinician will review your results and tailor any interpretation to you. See our Editorial Policy for how we write and review content.
Common questions about Progesterone
What is a normal Progesterone range?
Mid-luteal (about 7 days before the next period): over 30 suggests ovulation (nmol/L; timing to the individual cycle is critical). Follicular phase (before ovulation): low (under 5) (nmol/L). Always interpret your own results against the laboratory range printed on your report, since assay-specific reference ranges vary.
What does a low Progesterone result mean?
A mid-luteal level that is low can indicate that ovulation did not occur that cycle, or that the test was mistimed relative to your actual ovulation. The test is often repeated with careful cycle timing.
What does a high Progesterone result mean?
A high mid-luteal progesterone confirms ovulation. Progesterone is also high in pregnancy.
Do I need to fast or prepare for the Progesterone blood test?
Timing is everything: the sample should be taken about 7 days before the next expected period (adjusted for your own cycle length), not simply on "day 21", which only applies to a 28-day cycle. A morning sample is preferred.
Can I order a Progesterone blood test privately in London?
Yes. WMG Health offers Progesterone as part of bespoke panels and several pre-built panels at our 134 Harley Street clinic. Results are clinician-reviewed by a GMC-registered doctor within 4 hours for the most common assays. All panels are custom-built around your specific question; bookings via /contact/ or 020 3239 3378.