Understanding Your hCG Levels During Pregnancy: What’s Normal in Each Week?

hCG plays an important role in supporting your pregnancy. Read on to learn about what, exactly, it does, how your levels of it will change week-by-week, and what this hormone means for you and your baby.

Human chorionic gonadotropin (hCG) is the hormone produced by the cells surrounding your embryo that will eventually form the placenta. 1

Initially, hCG helps maintain the corpus luteum, a mass of cells that produces progesterone to create a supportive environment for your baby in your uterus. 2

Early on in your pregnancy, your levels of hCG will rise. As the placenta develops, it will take over progesterone production, eventually causing your hCG levels to decrease as the corpus luteum degenerates.

Beyond its primary function of supporting the corpus luteum, hCG is linked to some of the more infamous early pregnancy symptoms, like nausea (morning sickness), vomiting, and fatigue. Some researchers also believe it actually temporarily weakens your immune system to prevent your body from rejecting your pregnancy, which may contribute to morning sickness. 3

When does hCG become detectable?

You or your doctor may be able to detect hCG as early as 10 days after conception. 4 If you’ve ever taken a home pregnancy test before, this hormone is what that test was looking for.

hCG can be detected with:

• Urine tests: Urine tests (like at-home pregnancy tests) can detect hCG levels between 20 to 50 mIU / mL. You’ll typically reach these levels around the time your period would have been due, or 12 to 16 days after conception (depending on when you ovulated), which is the earliest you can take a pregnancy test. 5
• Blood tests: If you want a more accurate (and earlier) reading, a blood test is the way to go. They’re much more sensitive than urine tests and are capable of detecting hCG levels as low as 5 mIU / mL, which is usually possible around 10 days after conception. 6 However, blood tests aren’t available over the counter like urine tests; you’ll need to visit your doctor to get one done.

If you test yourself at home (with a urine test), to increase your chances of getting an accurate result, you should take the test first thing in the morning when your urine is most concentrated. 5

Note that testing too early—before your period would have ordinarily been due—can lead to getting a false negative pregnancy test result because your hCG levels might not be high enough yet. If you suspect you’re pregnant but get a negative result, wait a few days and try again.

What symptoms are associated with elevated hCG levels?

As mentioned, as your hCG surges, you may experience: 7

• Nausea and vomiting (morning sickness) 8
• Fatigue
• Breast tenderness
• Dizziness
• Food cravings or aversions
• Intestinal changes (like constipation)
• Increased urination

These symptoms vary widely. For example, some women experience intense nausea, while others have mild or no symptoms.

Just in case you need to report anything to your doctor, it’s a good idea to record what you’re experiencing in a journal, calendar, or pregnancy tracker app.

Most pregnancies don’t require regular hCG testing. Once your hCG level rises enough for you to get that first positive pregnancy test, you typically don’t need to think much about it anymore.

However, your doctor may continue to monitor your levels in specific situations:

• Risk of miscarriage: If there’s some reason to suspect you have a threatened early miscarriage, regular hCG measurements, taken 2–3 days apart, can help determine if your pregnancy is progressing as expected. 6 Your doctor will probably use an ultrasound to check for and potentially diagnose this when your baby’s heartbeat is detected, which generally happens around week 5 or week 6 of your pregnancy. 9
• Suspected ectopic pregnancy: An ectopic pregnancy is one that develops outside the uterus, which is a dangerous pregnancy complication. If your hCG levels rise abnormally or plateau, an ultrasound is needed to confirm your pregnancy’s location. 6
• IVF pregnancies: In-vitro fertilization (IVF) patients often undergo closer hCG monitoring to track implantation success. 10

Note that a single hCG test is not diagnostic—doctors look for patterns and trends over time.

Your levels of hCG will typically double every 48 to 72 hours in early pregnancy and peak around week 10. They’ll start declining once the placenta takes over hormone production. 11

To give you a better idea of what’s considered normal, check out the chart below for an overview of what levels of hCG doctors expect to see in each week of pregnancy: 4 6

Normal hCG levels week-by-week

After week 18 of your pregnancy, your hCG concentration will continue to taper off.

Note that these are just average ranges for hCG levels during different weeks of pregnancy, and your exact levels may vary significantly.

There are several factors that affect them, including the number of trophoblastic cells you develop (the cells that help the embryo attach to the uterus). That amount isn’t set in stone and varies from pregnancy to pregnancy. 12

Your doctor will probably focus on the trends in your hCG production rather than the specific numbers you reach since individual levels can vary so widely.

If your hCG levels are significantly outside the norm for how far along you are in your pregnancy, don’t panic. That doesn’t necessarily indicate a problem (although it can). Regardless, whatever’s going on, your doctor will take steps to handle it.

Below, we’ve listed several possible explanations for your unusual hCG production.

What high hCG levels can mean

If you have unusually high levels of hCG, that could indicate:

• Multiple pregnancy: Carrying twins or more often results in higher hCG levels. 6
• Molar pregnancy: This is a rare complication where abnormal tissue forms instead of an embryo. 13
• Certain cancers: High hCG levels can indicate certain cancers in rare cases. 6

Again, a high hCG level does not automatically indicate a problem (in fact, if you were hoping for twins, it’s possible it’s a good sign). You’ll need further tests from your doctor to determine the cause.

The hook effect

Extremely high hCG levels (like in twin pregnancies) can sometimes cause false negatives on home pregnancy tests. This process is known as the hook effect. 14 If your initial pregnancy tests yielded confusing results and you ended up being pregnant, this could be the culprit.

What low hCG levels can mean

Lower-than-expected hCG levels could suggest: 6

• Early (healthy) pregnancy: Some pregnancies naturally start with lower levels. If your hCG levels are a bit under what you were expecting, you could just be on the lower end of normal.
• Ectopic pregnancy: Again, this is a pregnancy in which implantation occurs outside the uterus, which usually causes the embryo to die. This can be extremely dangerous, so if your doctor determines you have an ectopic pregnancy, you’ll need treatment immediately.
• Miscarriage: Declining hCG levels are one of the signs of miscarriage, meaning you’ve suffered a pregnancy loss and you’re no longer pregnant.

Here again, a single low reading isn’t necessarily a concern. 15 Your doctor will look at your overall hCG trends and may conduct further tests before drawing any firm conclusions.

Can you influence your own hCG levels?

It’s natural to want to take control of your hormones and do whatever you can to ensure you have a healthy pregnancy, but there’s nothing you can do to directly raise or lower your hCG levels. 15

Just focus on maintaining a healthy lifestyle, attend all of your prenatal appointments, and discuss any concerns with your doctor.

This characteristic pregnancy hormone can be tricky to understand. There’s a wide range of what’s considered normal when it comes to your weekly hCG progression, so don’t get too caught up in the details.

Your doctor will keep a close eye on you and address any potential problems they see. Again, focus on staying healthy, getting plenty of rest, and counting down the days until you finally meet your little bundle of joy!