Progesterone test: normal ranges and what the result means
Below 1 ng/ml, converted to nmol/l (×3.18)
- Updated
- 2026-09-10
- Every number with its source
What progesterone is and why it is tested
Progesterone is a steroid hormone produced in a woman’s body mainly by the corpus luteum — a temporary gland that forms in the ovary after ovulation. It prepares the lining of the womb for the possible implantation of a fertilised egg and supports early pregnancy until the placenta takes over that role. That is why the amount of progesterone in the blood varies greatly with the phase of the cycle: it is low before ovulation, rises sharply after ovulation, and during pregnancy keeps rising right up to birth.
A small amount of progesterone is also made in the adrenal glands, so the hormone is tested in both women and men, although its clinical significance is mostly linked to women’s reproductive health. The test helps to assess whether ovulation has taken place, to monitor infertility treatment, to look into the causes of recurrent miscarriage and to assess how a pregnancy is progressing — especially when an ectopic pregnancy or a risk of miscarriage is suspected. Because the values depend on the day of the cycle and on the trimester of pregnancy, the result always has to be assessed together with a doctor, knowing the exact date of the last period or of the pregnancy.
Progesterone reference ranges
| Group | Reference, nmol/l | Source | |
|---|---|---|---|
| Women, before ovulation (follicular phase) Below 1 ng/ml, converted to nmol/l (×3.18) | less than 3.18 | MedlinePlus Reviewed 2025-05-22 | |
| Women, after ovulation (luteal phase) 5–20 ng/ml, converted to nmol/l (×3.18) | 15.90–63.60 | MedlinePlus Reviewed 2025-05-22 | |
| Pregnancy, first trimester 11.2–90.0 ng/ml, converted to nmol/l (×3.18) | 35.62–286.20 | MedlinePlus Reviewed 2025-05-22 | |
| Pregnancy, second trimester 25.6–89.4 ng/ml, converted to nmol/l (×3.18) | 81.41–284.29 | MedlinePlus Reviewed 2025-05-22 | |
| Pregnancy, third trimester In the source the interval rises through the trimester: 48–150–300 ng/ml or more (152.64–477–954 nmol/l or more, ×3.18). The upper limit is open (“or more”) — the exact level depends on the particular week of pregnancy | 152.64–954 | MedlinePlus Reviewed 2025-05-22 | |
According to MedlinePlus, the amount of progesterone in a woman’s blood depends on the phase of the menstrual cycle: before ovulation (in the follicular phase) it is usually below 3.18 nmol/l, and after ovulation (in the luteal phase), when, in the words of the source, “the level of progesterone in the blood starts to rise mid-cycle, keeps rising for another 6–10 days and then falls if the egg is not fertilised”, it rises to 15.90–63.60 nmol/l. That is why the same woman can get results that differ several times over on different days of her cycle, and the result has to be compared with the interval that matches the exact phase of the cycle rather than with one general “women’s range”. MedlinePlus also notes that different laboratories may use different assay methods, so the reference limits differ slightly between laboratories.
MedlinePlus states that during pregnancy the progesterone level keeps rising: the interval in the first trimester is 35.62–286.20 nmol/l, in the second trimester 81.41–284.29 nmol/l, and in the third trimester 152.64–954 nmol/l and more. The source explains that “progesterone levels continue to rise in early pregnancy”, which is why each trimester is given a separate, consistently higher interval than outside pregnancy. The upper limit for the third trimester is given as open (“or more”), because the exact level depends on the particular week of pregnancy. MedlinePlus also points out that reference limits can differ slightly between laboratories, so the result you get has to be assessed together with the week of pregnancy and the interval given by that particular laboratory, not only with the figures shown here.
When a progesterone test is done
- To assess whether a woman is ovulating — when it is difficult to conceive, or when infertility treatment is being monitored
- When periods are irregular or there is unexpected bleeding from the womb and you are not pregnant
- When an ectopic pregnancy or a risk of miscarriage is suspected in early pregnancy
- To monitor a high-risk pregnancy, or how well progesterone therapy is working
- To look into the causes of recurrent miscarriage
- When an adrenal or ovarian disorder is suspected and there are other signs of hormonal imbalance
How to prepare
- No special preparation is usually needed, but it is useful to know the exact date of the last period or of the pregnancy, because it determines which interval the result will be compared with
- Your doctor may ask you to stop taking certain medicines before the test — you are told about this in advance
The general rules that apply to any blood draw are gathered in a separate article on how to prepare for a blood test.
A raised progesterone level
In women who are not pregnant, a raised progesterone level can be linked to an ovarian cyst or to rare ovarian or adrenal diseases. In pregnant women it can be linked to a multiple pregnancy or to a molar pregnancy. During ovulation progesterone rises physiologically — that is normal, so the result has to be assessed together with the day of the cycle and with whether you are pregnant.
- Ovulation — a physiological, temporary rise in progesterone in the middle of the cycle
- Pregnancy, especially a multiple pregnancy
- A molar pregnancy (a disorder of the pregnancy tissue)
- A cyst in the ovaries
- Ovarian cancer (rarely)
- Adrenal cancer (rarely)
- Congenital adrenal hyperplasia (rarely)
What to discuss with a doctor
- Whether the result matches the day of the cycle or the trimester of pregnancy — without this information the value is hard to interpret
- An ultrasound scan of the ovaries, if a cyst or a tumour is suspected
- Other hormone tests (oestradiol, LH, FSH) that help to assess the overall hormonal picture
- In pregnancy — an ultrasound scan, to rule out a multiple pregnancy or a molar pregnancy
A low progesterone level
Outside pregnancy, a low progesterone level most often shows that ovulation did not take place during that cycle, or is linked to polycystic ovary syndrome or to thyroid disorders. During pregnancy a low progesterone level can be linked to an ectopic pregnancy or to an increased risk of miscarriage, which is why it is assessed urgently.
- Absence of ovulation (anovulation), because of which periods do not happen (amenorrhoea)
- Polycystic ovary syndrome (PCOS)
- An irregular menstrual cycle
- Thyroid disorders
- A raised level of prolactin in the blood
- An ectopic pregnancy, a miscarriage or fetal death
- Severe stress or perimenopause
What is usually assessed after a low result
- Whether the menstrual cycle is regular and whether there were signs of ovulation
- In pregnancy — an urgent ultrasound scan, to rule out an ectopic pregnancy or a threatened miscarriage
- Thyroid (TSH) and prolactin tests, if the cycle is irregular
- A repeat test at another point in the cycle, to confirm ovulation
How to read the result, and related pages
A single progesterone figure does not name a cause on its own: the value is interpreted by a doctor together with the day of the cycle or the week of pregnancy, and alongside the other tests. Because laboratories may use different assay methods, reference limits differ slightly between them, so the most accurate guide is the interval printed on your own report. Related pages: oestradiol, LH, FSH, prolactin, AMH, beta-hCG, tests during pregnancy in Lithuania and how to read blood test results.
Full site in Lithuanian: proactiva.app
Frequently asked questions
›What is the normal progesterone range?
According to MedlinePlus, in women before ovulation progesterone is usually below 3.18 nmol/l, and after ovulation it rises to 15.90–63.60 nmol/l. During pregnancy the concentration keeps rising: 35.62–286.20 nmol/l in the first trimester, 81.41–284.29 nmol/l in the second, and in the third trimester it can reach and exceed 900 nmol/l. You will find the exact interval used by your laboratory on your own report.
›When is the best time to test progesterone if I want to check ovulation?
To confirm ovulation, progesterone is most often tested in the middle of the cycle or in the second half of the cycle, when the level should be noticeably raised after ovulation. It is worth agreeing the exact day with your doctor, according to the length of your individual cycle.
›Does low progesterone mean I will not be able to conceive?
A low progesterone level can indicate that ovulation did not take place in that cycle, but it does not necessarily mean permanent infertility. A cause such as PCOS or a thyroid disorder can be identified and discussed with a doctor, who will choose the tests to be done next.
›Do I need any special preparation for a progesterone test?
According to MedlinePlus, no special preparation is usually needed, but it is useful to know the exact date of the last period or of the start of the pregnancy. Your doctor will let you know if you need to stop taking certain medicines before the test.
›Why is progesterone tested during pregnancy?
During pregnancy progesterone helps to assess whether the pregnancy is developing as it should — a low level can be linked to an ectopic pregnancy or to an increased risk of miscarriage, so such a result is usually assessed urgently together with an ultrasound scan.
›How does progesterone differ from oestradiol?
Oestradiol dominates in the first half of the cycle and builds the follicle, while progesterone rises after ovulation and prepares the womb for a possible pregnancy. The two hormones are often assessed together, in order to assess how the menstrual cycle as a whole is going.
Sources
- MedlinePlus (US National Library of Medicine): Serum progesterone — 2026-09-07
- MedlinePlus: Progesterone Test — 2026-09-07
Related markers
This site is not an emergency service. If severe chest or head pain, breathlessness, confusion, difficulty speaking, heavy bleeding or another acute problem has come on suddenly — do not wait for tests, call 112.
This information is not a diagnosis and does not replace a consultation with a doctor. Reference ranges depend on the laboratory, your age and sex — always compare your result with the range printed on your own report.