hCG Levels by Week: Chart & Normal Ranges

If you've just received your hCG (human chorionic gonadotropin) blood test result and you're trying to work out whether everything is on track, you're not alone. It's one of the first markers doctors use to confirm and follow a pregnancy in its earliest days. Let's calmly walk through what hCG is, what normal hCG levels look like by week, how quickly the number should rise, and what low or high values can mean.

First, the key point: a single hCG value on its own tells you almost nothing. Your doctor always looks at the trend — how the number changes over a few days — together with an ultrasound. So don't rush to draw conclusions from one figure on a lab slip.

What hCG is and why it rises in pregnancy

To answer the most common question — "what is hCG?" — it's a hormone produced by the trophoblast, the embryonic tissue that later develops into the placenta. It starts to be released soon after a fertilized egg attaches to the wall of the uterus (implantation), appearing first in the blood and then in the urine.

Its job is to support the corpus luteum in the ovary, which produces progesterone and "holds" the pregnancy through those very first weeks until the placenta takes over. Because this hormone appears almost only in pregnancy, every test — home and lab alike — is built around detecting it.

The hCG molecule has two parts — an alpha and a beta subunit. Labs measure the beta part specifically, which is why the quantitative blood test is often called beta hCG. It's the same hormone, just a more precise name for the test.

hCG dynamics: doubling time and the peak

In the first weeks of pregnancy, hCG rises very quickly. In a normally developing intrauterine pregnancy, the level roughly doubles every 48–72 hours (two to three days). This is the well-known hCG doubling time. Closer to 6–7 weeks, once the values are already high, doubling naturally slows and takes 3–4 days — and that's normal.

hCG peaks at around 8–11 weeks of pregnancy. After that the level eases down and, by mid-pregnancy, settles onto a plateau, staying relatively stable until birth. So a "drop" in hCG during the second trimester isn't a cause for worry — it's simply how things usually go.

Why the trend matters more than a single number

The range of normal values at each week is enormous (you'll see this in the chart below), so one figure decides little. Far more informative are two tests 48 hours apart, run by the same lab. If hCG has risen confidently over that time, that's a good sign. If the increase is very weak (say, less than a third over 48 hours) or the level is falling, your doctor will look into why, together with an ultrasound. A single result is a photograph; the trend is a film.

hCG levels by week: the chart

Below is an approximate chart of hCG levels by gestational (obstetric) week. One important note: gestational age is counted from the first day of your last period, not from conception (actual conception happens about 2 weeks later). If you're unsure of your dates, go by how your doctor dated the pregnancy or by your first ultrasound. We explain how weeks and trimesters work in our guide to how long pregnancy lasts: weeks, trimesters, and your due date.

Values are given in mIU/mL (the same as mU/mL — no conversion needed). Notice how wide the "normal" boundaries are: that isn't an error, it's just the nature of this marker.

As you can see, at the very same week both 8,000 and 200,000 can be normal. So if your number falls within that wide corridor, all is well — and if it doesn't, that still isn't a diagnosis, just a reason to check the trend and have an ultrasound. And, once more: this chart is an average. Your own lab may have its own reference ranges, and those are the ones to go by.

hCG and the pregnancy test: blood or urine

A home test strip reacts to hCG in urine, but only qualitatively — "yes" or "no" — and usually picks the hormone up a little later. The beta hCG blood test is quantitative: it gives an exact number and can "see" a pregnancy earlier, sometimes even before a missed period. We cover the different types of tests and how they differ in our piece on early pregnancy signs before a missed period.

When should you test? A blood hCG test only makes sense from about 10–14 days after presumed conception; any earlier and the value may still be too low. Testing too soon is a common cause of needless disappointment. For the most accurate timing, see our separate guide on when to take a pregnancy test for an accurate result.

When a pregnancy becomes visible on ultrasound

hCG and ultrasound complement each other. A gestational sac in the uterus usually becomes visible on a transvaginal ultrasound once hCG reaches roughly 1,000–2,000 mIU/mL (this is called the "discriminatory zone"). If hCG is already high but nothing is seen in the uterine cavity on ultrasound, your doctor will work to rule out an ectopic pregnancy. For when and what the scan shows, see our article on the first ultrasound in pregnancy.

What abnormal hCG values can mean

A number that's off the chart can be frightening, but on its own it diagnoses nothing. Let's calmly go through what low and high values can mean.

Low hCG levels or a slow rise

Possible reasons (from the most common and harmless to those that need attention):

• Miscalculated dates. The most common "cause" of low hCG is that ovulation happened later than thought, and you're simply earlier along than the calendar suggests.
• Ectopic pregnancy. Here hCG often rises slowly and doesn't double as it should. If pain and spotting are also present, see a doctor urgently. The warning signs are listed in our article on the symptoms of an ectopic pregnancy.
• Missed miscarriage or a threatened one. Falling hCG in the first trimester can point to a pregnancy that has stopped developing, but this is confirmed only by ultrasound and the trend.

High hCG

A value higher than expected is most often linked to pleasant or neutral causes:

• Multiple pregnancy. Twins or triplets produce more of the hormone, so hCG is naturally higher.
• An earlier conception date than assumed — meaning you're actually further along than you thought.
• A molar pregnancy — a rare condition in which trophoblast tissue grows abnormally; hCG can be very high with it. It's uncommon and is picked up on ultrasound.

One more note on free beta hCG as part of first-trimester prenatal screening: there the result is reported not in absolute units but in MoM, and a high or low free beta hCG in MoM is only a risk estimate, not a diagnosis. Interpreting the screening is your doctor's job, alongside the ultrasound and other markers.

How to take the test and read your result correctly

A few practical rules to help you get a reliable hCG reading:

• Venous blood is drawn; strict fasting isn't required, but a morning test without a big meal beforehand gives a steadier result.
• Look at your own lab's reference ranges printed next to your number on the slip — charts from the internet are only a rough guide.
• Don't compare results from different labs. They use different test systems, and the same number can mean different things. If you need to assess the trend, have both tests done at the same lab.
• The units mIU/mL and mU/mL are the same thing — there's nothing to convert.

And remember: an "hCG chart" and online calculators are handy for a general picture, but the final interpretation is always made by your doctor, looking at your dates, the trend and the ultrasound together.

When to seek urgent medical help

An hCG result on its own is no reason to panic. But you should get help without delay if, alongside a slowly rising or falling hCG, you develop:

• severe lower-abdominal pain, especially on one side;
• bleeding or heavy spotting;
• sudden weakness, dizziness or fainting;
• pain in the shoulder or under the shoulder blade together with abdominal pain.

This combination can point to an ectopic pregnancy and needs urgent medical assessment. Otherwise, calmly discuss your numbers with your gynecologist — usually everything is settled with a repeat test and an ultrasound.

Key takeaways

• hCG is the pregnancy hormone made by the trophoblast (the future placenta); the blood test measures its beta part — beta hCG.
• In early pregnancy hCG roughly doubles every 48–72 hours, peaks at 8–11 weeks, then eases down.
• Normal hCG levels by week are very wide and depend on the lab — the chart is only a guide.
• A single value isn't informative: the trend matters more (two tests 48 hours apart at the same lab) plus an ultrasound.
• Low or slow-rising hCG can mean miscalculated dates, an ectopic or a missed miscarriage; high hCG can mean twins, an earlier date, or a rare molar pregnancy. Your doctor clarifies all of this.
• Seek urgent care for pain, bleeding and weakness alongside an abnormal hCG trend.

This article is general information and is not a substitute for personalized medical advice. Be sure to discuss your hCG results and any worrying symptoms with the obstetrician-gynecologist caring for you.