Lab result explainedHormonesLast updated November 10, 2026

hCG blood test: levels by week, doubling time, and what low or high hCG means

hCG (quantitative blood test) (hCG) · Quantitative beta-hCG (ordered alone or with progesterone) · reported in mIU/mL (equivalent to IU/L)

Human chorionic gonadotropin (hCG) is the hormone made by the placenta from the moment an embryo implants, and a quantitative hCG blood test measures exactly how much is in your blood in milli-international units per millilitre (mIU/mL). Below 5 mIU/mL is negative, above 25 is positive for pregnancy, and 5 to 25 is indeterminate and repeated in two days. Blood can detect hCG about 6 to 8 days after ovulation, several days before a urine test, and the number gives information a urine test cannot: how far along a pregnancy is likely to be, whether it is progressing normally, and whether something is wrong.

In a normal early pregnancy hCG roughly doubles every 48 to 72 hours, reaches a peak of up to 100,000 to 290,000 mIU/mL around weeks 8 to 11, then falls and settles at a lower plateau for the rest of pregnancy. Because the normal range at any week is enormous (at 5 weeks it runs from about 18 to over 7,000), a single number says little about dates or about how the pregnancy is doing; the rate of change between two tests 48 hours apart is what clinicians use. A rise of less than about 35 to 50 percent in 48 hours, a plateau, or a fall is the pattern that raises concern for miscarriage or ectopic pregnancy.

hCG is also measured outside pregnancy. It is a tumor marker for testicular and ovarian germ cell tumors and for gestational trophoblastic disease (molar pregnancy), where values can exceed 100,000 and are tracked to zero after treatment. Low levels of up to about 14 mIU/mL can come from the pituitary gland in women around and after menopause, and fertility treatment that uses an hCG trigger injection leaves detectable hCG for up to 10 to 14 days. Each of these can produce a positive result that is not a pregnancy.

hCG at a glance

What it is: the pregnancy hormone made by the placenta; the quantitative blood test gives a number in mIU/mL (the same as IU/L) rather than a yes or no.
Not pregnant: below 5 mIU/mL. Indeterminate: 5–25, repeat in 48 hours. Pregnant: above 25. Postmenopausal women can run up to about 14 from the pituitary.
Levels by week are very wide (4 weeks from last period: 5–426; 5 weeks: 18–7,340; 6 weeks: 1,080–56,500; peak 8–11 weeks up to about 290,000), so one number cannot date a pregnancy reliably.
Doubling time: about every 48–72 hours below 1,200 mIU/mL; the minimum rise for a viable pregnancy is roughly 49 percent in 48 hours when the starting level is under 1,500, 40 percent from 1,500–3,000, and 33 percent above 3,000.
Low or slowly rising hCG suggests wrong dates, miscarriage or ectopic pregnancy; very high hCG suggests twins, wrong dates or a molar pregnancy.
Next step: a repeat level 48 hours later, and a transvaginal ultrasound once hCG is above about 1,500–3,500 mIU/mL, when a normal pregnancy should be visible in the uterus.

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What hCG measures

hCG is a two-part hormone made by the trophoblast cells that become the placenta. Its alpha chain is identical to that of LH, FSH and TSH; the beta chain is unique, which is why the test is often called beta-hCG. Its job in early pregnancy is to keep the corpus luteum making progesterone until the placenta can take over at around 8 to 10 weeks, which is also why hCG peaks then and falls afterwards. The same beta-chain similarity to TSH explains why very high hCG, as in twins or a molar pregnancy, can mildly overactivate the thyroid.

Quantitative assays measure intact hCG and, in most modern tests, some of its fragments, reported in mIU/mL against an international standard. Different manufacturers' assays can read 10 to 20 percent apart, so serial levels used to judge a pregnancy or track a tumor should come from the same laboratory. A qualitative blood test and a home urine test only report positive or negative, at thresholds of roughly 5 to 10 mIU/mL in blood and 20 to 25 in urine.

Two technical pitfalls matter. Heterophile antibodies in a small number of people cross-react with the assay and produce a persistent false-positive hCG (so-called phantom hCG), which is identified by a negative urine test and by diluting the sample. At extremely high levels, above about 500,000 mIU/mL as in some molar pregnancies, the assay can be overwhelmed and report a falsely low result (the hook effect), which is also solved by dilution. High-dose biotin supplements can interfere with some hCG immunoassays as well.

Normal range for hCG

Reference ranges vary between labs and by age, sex and pregnancy. Use the range printed on your own report.

Group	Typical range (mIU/mL (equivalent to IU/L))	Notes
Not pregnant (women of reproductive age and men)	Below 5 mIU/mL	5–25 is indeterminate: very early pregnancy, a failing pregnancy, recent miscarriage, or a non-pregnancy source. Repeat in 48 hours.
3–4 weeks from last menstrual period	5–426 mIU/mL	Implantation to the first missed period. Ranges are from large reference series; labs and individuals vary widely.
5 weeks	18–7,340 mIU/mL	A gestational sac is usually visible on transvaginal ultrasound once hCG is above about 1,500–2,000.
6 weeks	1,080–56,500 mIU/mL	A yolk sac and often a heartbeat become visible; an intrauterine pregnancy should be seen by 3,500 mIU/mL.
7–8 weeks	7,650–229,000 mIU/mL	Doubling slows to every 3 to 4 days as levels climb.
9–12 weeks (peak)	25,700–288,000 mIU/mL	Levels peak around weeks 8 to 11 and then fall, which is why nausea often eases in the second trimester.
13–24 weeks	4,060–254,000 mIU/mL	Falls to a plateau at roughly a quarter of the peak; still used in the second-trimester quad screen as a multiple of the median.
25–40 weeks	3,640–117,000 mIU/mL	Returns to below 5 mIU/mL within about 2 to 4 weeks of delivery, and within 4 to 6 weeks of a miscarriage or abortion.
Postmenopausal women (pituitary hCG)	Up to about 14 mIU/mL	Normal, non-pregnancy source once periods have stopped; confirmed by a high FSH. In men, anything above 5 needs an explanation.

High hCG

Because the normal range at each week is so wide, high hCG is mostly a matter of context: a level higher than expected for the dates, a level that is still high when it should be falling, or any level in someone who should have none. In early pregnancy the most common explanation for a higher-than-expected result is that the pregnancy is further along than the last period suggests, followed by twins or triplets, where levels run roughly double. Neither needs anything more than an ultrasound to confirm.

A very high hCG, often above 100,000 mIU/mL in the first trimester with severe vomiting, a uterus larger than expected, bleeding, or early high blood pressure, raises the possibility of a molar pregnancy (gestational trophoblastic disease), in which abnormal placental tissue grows without a normal fetus. Ultrasound makes the diagnosis; after the tissue is removed, hCG is measured weekly until it is normal and then monthly for up to 6 months, because a plateau or rise means the tissue has persisted and needs treatment. In the second-trimester quad screen, hCG about twice the median contributes to an increased Down syndrome risk estimate.

Outside pregnancy, a raised hCG has a short list of causes. In men, and in women with a pelvic mass, it points to a germ cell tumor: about half of non-seminomas and 15 to 25 percent of seminomas produce it. Choriocarcinoma and some lung, bladder, stomach and pancreatic cancers rarely secrete it. More benign explanations include the pituitary gland after menopause, a recent hCG trigger injection in fertility treatment, residual hCG in the weeks after a miscarriage, abortion or delivery, and a laboratory artefact from heterophile antibodies.

Common causes

Dates earlier than the pregnancy really is
The commonest reason a result looks high. Ovulating earlier than day 14, or misremembering the last period, shifts the expected range by thousands of mIU/mL; a dating ultrasound settles it.
Twins or higher multiples
Each placenta makes hCG, so levels run roughly double a singleton's at the same stage and sometimes exceed 100,000 early. The doubling time is normal.
Molar pregnancy and gestational trophoblastic disease
Complete moles commonly produce hCG above 100,000 mIU/mL and sometimes over 1 million, with vaginal bleeding, severe nausea and a large uterus; persistent disease after evacuation shows as a plateau (within 10 percent over 4 weekly values) or a rise (10 percent or more over 3 values).
Hyperemesis gravidarum
Severe pregnancy vomiting is associated with higher hCG, especially with multiples or a molar pregnancy; very high hCG can also suppress TSH and mimic hyperthyroidism.
Germ cell tumors
Testicular and ovarian non-seminomas (about 50 percent), seminomas (15 to 25 percent) and choriocarcinoma secrete hCG. Levels under 5,000, 5,000 to 50,000 and over 50,000 IU/L define good, intermediate and poor risk in testicular cancer.
Pituitary hCG after menopause
The pituitary makes small amounts of hCG alongside LH and FSH once ovarian hormones fall; values up to about 14 mIU/mL are normal in postmenopausal women and fall if an oral contraceptive is taken for 2 to 3 weeks.
hCG trigger injections in fertility treatment
A 5,000 to 10,000 IU trigger (or 250 micrograms of recombinant hCG) is detectable for 10 to 14 days, so a test within that window reflects the injection, not a pregnancy.
Residual hCG after a pregnancy ends
Levels fall with a half-life of 24 to 36 hours but can take 4 to 6 weeks to reach zero after a miscarriage or abortion; a level that stops falling suggests retained tissue or an ectopic pregnancy.
Other cancers
Lung, bladder, stomach, pancreatic, kidney and liver cancers very occasionally secrete hCG, usually at advanced stages, as do some neuroendocrine tumors.
Phantom hCG (heterophile antibodies)
Human antibodies that bind the assay reagents cause a persistent, usually low-level (5 to 200 mIU/mL) false positive; a negative urine test, serial dilution or a different assay unmasks it.

Symptoms that can go with it

Often none beyond the usual early pregnancy symptoms (nausea, breast tenderness, fatigue), which tend to be stronger with higher levels
Severe or persistent vomiting with weight loss or dehydration (hyperemesis), more common with twins and molar pregnancy
Vaginal bleeding, sometimes with passage of grape-like tissue, and a uterus larger than expected for dates (molar pregnancy)
High blood pressure or preeclampsia symptoms before 20 weeks, which is unusual and points to a molar pregnancy
Palpitations, heat intolerance, tremor or anxiety from hCG-driven thyroid overactivity
A painless testicular lump, breast swelling or tenderness in a man, or a pelvic mass in a woman (germ cell tumor)
A positive pregnancy test after menopause, with no other symptoms, which is usually pituitary hCG

Low hCG

A low hCG means less than expected for how far along a pregnancy is thought to be, or a level that is rising too slowly. The first and most common explanation is dates: ovulating late, or implanting late, puts the pregnancy a week or two behind the calendar, and a healthy pregnancy that is simply younger than assumed will show a normal rise on repeat testing. That is why a single low value is never used to diagnose a problem; the 48-hour trend is.

When hCG rises by less than about 35 to 50 percent over 48 hours, plateaus, or falls, the pregnancy is unlikely to be developing normally. The two possibilities are a miscarriage, including a pregnancy that never developed beyond a sac (anembryonic pregnancy) and a very early loss (chemical pregnancy), and an ectopic pregnancy, where the embryo has implanted outside the uterus, usually in a fallopian tube. Ectopic pregnancies typically produce lower and more slowly rising hCG, but their pattern overlaps with both normal and failing intrauterine pregnancies, so ultrasound is essential.

Ultrasound and hCG are read together. Once hCG is above the discriminatory level, set conservatively at 3,500 mIU/mL (some centers use 1,500 to 2,000), a normal pregnancy should be visible inside the uterus; an empty uterus at that level means either a failing pregnancy or an ectopic one, and in a woman with pain or bleeding that is treated as an ectopic pregnancy until proven otherwise. A falling hCG after a miscarriage should reach below 5 within 4 to 6 weeks; a level that stalls needs assessment for retained tissue or an ectopic pregnancy.

Common causes

Dates later than assumed
Late ovulation or late implantation is the most common reason for a low single value; the doubling time on repeat testing is normal and the ultrasound simply shows a younger pregnancy.
Miscarriage, including chemical and anembryonic pregnancy
Roughly 10 to 20 percent of recognized pregnancies end in miscarriage, most in the first trimester; hCG rises slowly, plateaus or falls, and ultrasound shows an empty sac or no heartbeat.
Ectopic pregnancy
About 1 to 2 percent of pregnancies, and the leading cause of first-trimester death; hCG is often under 1,500 with a rise of under 35 to 50 percent in 48 hours, though a minority rise normally, and the uterus is empty on ultrasound.
Resolving pregnancy
After a miscarriage, abortion or delivery hCG falls with a half-life of 24 to 36 hours and is usually below 5 mIU/mL within 2 to 6 weeks.
Hook effect at extremely high levels
Above roughly 500,000 mIU/mL, as in some molar pregnancies, the assay saturates and reports a falsely low or even negative result; diluting the sample reveals the true value.
Assay interference and biotin
High-dose biotin (5 mg a day or more, common in hair and nail supplements) can produce falsely low results on some immunoassays; stopping it for 2 to 3 days before testing avoids the problem.
Testing too early
Before implantation, which occurs 6 to 12 days after ovulation, there is no hCG at all; a blood test a few days before a missed period can be negative or indeterminate in a pregnancy that is perfectly healthy.

Symptoms that can go with it

Often none; a slow rise is frequently found on routine repeat testing
Vaginal bleeding or spotting and cramping, which occur in miscarriage but also in a third of normal early pregnancies
Pain on one side of the lower abdomen, especially with bleeding, which raises concern for ectopic pregnancy
Shoulder-tip pain, dizziness, fainting or a racing heart, which can mean internal bleeding from a ruptured ectopic pregnancy and is an emergency
Loss of early pregnancy symptoms such as nausea and breast tenderness, which is unreliable on its own
A positive home test that later turns negative (chemical pregnancy)

Read it alongside

Progesterone — a level under 5 ng/mL in early pregnancy strongly suggests a non-viable pregnancy, above 20 ng/mL a viable one, though it does not say where the pregnancy is.
Transvaginal ultrasound — not a blood test, but inseparable from hCG interpretation; an intrauterine sac should be visible once hCG exceeds about 1,500–3,500 mIU/mL.
FSH — a high FSH alongside a low positive hCG in a woman over 45 confirms the pituitary, not a pregnancy, as the source.
TSH and free T4 — very high hCG can suppress TSH and mimic hyperthyroidism in the first trimester, usually without needing treatment.
AFP and LDH — the other germ cell tumor markers, measured with hCG in a man with a testicular mass; AFP, unconjugated estriol and inhibin A join hCG in the second-trimester quad screen.
Hemoglobin — checked when bleeding is heavy or an ectopic pregnancy is suspected.
Blood group and Rh status — anyone with bleeding in early pregnancy who is Rh-negative may need anti-D immunoglobulin.
Urine hCG — a negative urine test with a persistently positive blood test points to phantom hCG from heterophile antibodies.

What usually happens next

An indeterminate (5–25) or low result is repeated after 48 hours at the same lab; a rise of at least 49 percent from a starting level under 1,500 mIU/mL (40 percent from 1,500–3,000, 33 percent above 3,000) is consistent with a viable pregnancy.
Once hCG is above about 1,500–3,500 mIU/mL, a transvaginal ultrasound is arranged to confirm the pregnancy is in the uterus; with pain or bleeding this is done the same day regardless of the level.
If hCG plateaus or falls, ultrasound and sometimes a further level distinguish a miscarriage from an ectopic pregnancy; after a miscarriage, levels are followed until below 5 mIU/mL.
After a molar pregnancy, expect weekly hCG until normal and then monthly for 6 months (complete mole) or 1 month (partial mole); avoid pregnancy during follow-up so a rise is not misread.
A positive hCG in a man, or in a postmenopausal woman with no pituitary explanation, is followed by a testicular or pelvic ultrasound and a repeat on a different assay.
Tell the lab if you have had an hCG trigger injection within 2 weeks, take high-dose biotin, or have had a recent pregnancy loss.

Diet, lifestyle and natural levers with evidence

What can move hCG once the cause is known. Nothing here replaces finding the cause.

Test at the right time

Strong evidence

Nothing dietary, herbal or lifestyle-related raises or lowers hCG; the level is set by the placenta or the tissue producing it. What you control is timing. hCG appears 6 to 12 days after ovulation and crosses 25 mIU/mL around the first missed period in most pregnancies, so a blood test taken before that can be negative or indeterminate in a healthy pregnancy, and an hCG trigger injection in fertility treatment makes a test within 10 to 14 days meaningless. Testing on or after the day of the expected period, and repeating 48 hours later rather than reacting to one number, gives a reliable answer.

Stop high-dose biotin before testing and declare medications

Moderate evidence

The US Food and Drug Administration has warned that biotin at the 5 to 10 mg doses sold for hair, skin and nails interferes with immunoassays that use biotin-streptavidin chemistry, which includes some hCG, troponin and thyroid tests, producing falsely low or falsely high results. Case reports include falsely negative hCG. Stopping biotin for 2 to 3 days before a blood test removes the interference; prenatal vitamins (30 to 300 micrograms) do not cause it. Progesterone, folic acid and prenatal vitamins do not change hCG.

Not smoking in and before pregnancy

Moderate evidence

Smoking lowers measured hCG by roughly 10 to 20 percent in second-trimester screening programs, enough that laboratories adjust the multiple of the median for smokers, and it more than doubles the risk of ectopic pregnancy and raises the risk of miscarriage, the two problems a low or slowly rising hCG flags. Stopping before conception removes both effects; there is no supplement with evidence of raising hCG or rescuing a pregnancy with a falling level.

When to see a clinician promptly

A positive hCG with one-sided pelvic pain, shoulder-tip pain, dizziness, fainting or a racing heart: possible ruptured ectopic pregnancy, which is life-threatening and needs emergency care immediately.
Any bleeding or pain in early pregnancy with a known low or slowly rising hCG, for same-day ultrasound.
Heavy bleeding soaking a pad an hour for 2 hours, or passage of tissue, with cramping.
Vomiting so severe you cannot keep fluids down, with weight loss or dark urine, particularly if hCG is very high.
An hCG that plateaus or rises after a miscarriage, abortion or molar pregnancy, which can mean retained or persistent trophoblastic tissue.
A positive hCG in a man, or with a testicular lump at any age, for urgent ultrasound.

Frequently asked questions

What hCG level confirms pregnancy?

Above 25 mIU/mL on a quantitative blood test is considered positive, below 5 negative, and 5 to 25 indeterminate, which is repeated in 48 hours. A positive result confirms that hCG-producing tissue is present, which is almost always a pregnancy, but it does not confirm that the pregnancy is in the uterus or developing normally; a repeat level and, later, an ultrasound do that.

What are normal hCG levels by week?

Counting from the last menstrual period: 3 weeks 5–50, 4 weeks 5–426, 5 weeks 18–7,340, 6 weeks 1,080–56,500, 7–8 weeks 7,650–229,000, 9–12 weeks 25,700–288,000, 13–16 weeks 13,300–254,000, 17–24 weeks 4,060–165,400 and 25–40 weeks 3,640–117,000 mIU/mL. These ranges are so wide that a single value cannot date a pregnancy or judge its health; the 48-hour rise and ultrasound are what matter.

How fast should hCG double?

In a normal early pregnancy hCG doubles roughly every 48 to 72 hours while levels are under about 1,200 mIU/mL, every 72 to 96 hours from 1,200 to 6,000, and more slowly above that. The minimum rise still consistent with a viable pregnancy is about 49 percent over 48 hours from a starting level under 1,500, 40 percent from 1,500 to 3,000, and 33 percent above 3,000. A smaller rise does not prove a problem but prompts an ultrasound.

What does low hCG mean?

Most often that the pregnancy is younger than the dates suggest, in which case the next test shows a normal rise. If the level rises slowly, plateaus or falls, the pregnancy is probably not developing normally and the two possibilities are miscarriage and ectopic pregnancy. Neither is diagnosed from one number; a repeat in 48 hours and a transvaginal ultrasound are the next steps, and pain or bleeding should be assessed the same day.

Can you have a healthy pregnancy with low hCG?

Yes. The normal range at every week is very wide, and plenty of healthy pregnancies start at the low end, particularly with late ovulation or late implantation. What matters is the trend: a low level that rises by at least a third to a half every 48 hours and leads to a pregnancy visible in the uterus with a heartbeat is a normal pregnancy, whatever the starting number.

What is the hCG level for twins?

Twins tend to produce hCG around twice the singleton level at the same stage, and values over 100,000 mIU/mL can appear early, but the ranges overlap so much that hCG cannot diagnose twins. Only ultrasound can. A high hCG with a normal doubling time most often means twins or dates that are off; a very high hCG with bleeding or severe vomiting raises the question of a molar pregnancy.

How long does hCG stay in your system after miscarriage?

hCG falls with a half-life of about 24 to 36 hours once the pregnancy tissue is gone, so it typically returns to below 5 mIU/mL within 2 to 6 weeks of a miscarriage or abortion, faster from a low starting level. Home tests may stay positive for 2 to 3 weeks. A level that stops falling suggests retained tissue or, rarely, an ectopic pregnancy or persistent trophoblastic disease, and is investigated.

Can hCG be positive if you are not pregnant?

Yes. Pituitary hCG in women around and after menopause can reach about 14 mIU/mL; an hCG trigger injection is detectable for 10 to 14 days; levels linger for weeks after a pregnancy ends; germ cell tumors of the testis or ovary and gestational trophoblastic disease secrete it; a few other cancers rarely do; and heterophile antibodies cause a laboratory false positive that a urine test will not show. A positive hCG in a man always needs an explanation.

References

Pregnancy test. MedlinePlus, US National Library of Medicine (2023)View source
HCG blood test - quantitative. MedlinePlus Medical Encyclopedia (2023)View source
American College of Obstetricians and Gynecologists. ACOG Practice Bulletin No. 193: Tubal ectopic pregnancy. Obstetrics & Gynecology (2018)
American College of Obstetricians and Gynecologists. ACOG Practice Bulletin No. 200: Early pregnancy loss. Obstetrics & Gynecology (2018)
Barnhart KT, Sammel MD, Rinaudo PF, et al.. Symptomatic patients with an early viable intrauterine pregnancy: hCG curves redefined. Obstetrics & Gynecology (2004)
Barnhart KT, Guo W, Cary MS, et al.. Differences in serum human chorionic gonadotropin rise in early pregnancy by race and value at presentation. Obstetrics & Gynecology (2016)
Connolly A, Ryan DH, Stuebe AM, Wolfe HM. Reevaluation of discriminatory and threshold levels for serum beta-hCG in early pregnancy. Obstetrics & Gynecology (2013)
Doubilet PM, Benson CB, Bourne T, et al.. Diagnostic criteria for nonviable pregnancy early in the first trimester. New England Journal of Medicine (2013)
Snyder JA, Haymond S, Parvin CA, Gronowski AM, Grenache DG. Diagnostic considerations in the measurement of human chorionic gonadotropin in aging women. Clinical Chemistry (2005)
Cole LA. Biological functions of hCG and hCG-related molecules. Reproductive Biology and Endocrinology (2010)
Ngan HYS, Seckl MJ, Berkowitz RS, et al.. Update on the diagnosis and management of gestational trophoblastic disease (FIGO Cancer Report 2021). International Journal of Gynecology & Obstetrics (2021)

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This page is educational and is not medical advice or a diagnosis. Lab results have to be interpreted together with your history, symptoms and other results by a clinician who knows you. Do not start or stop a supplement to change a lab value before the cause is known.