Using an hCG Levels Chart To Monitor Your Pregnancy

Human chorionic gonadotropin (hCG) is a hormone produced during pregnancy in the cells of the placenta. The presence of hCG triggers at-home pregnancy tests to turn positive.

The amount of hCG in a pregnant person's body rises rapidly during early pregnancy. While it's not a standard practice, charting hCG levels can help determine whether the pregnancy is progressing normally, is at risk for a miscarriage, or is showing signs of other complications.

Below, we take a more in-depth look at hCG levels, how they're measured, and what they can mean throughout your pregnancy. We also provide a handy hCG levels chart for parents-to-be.

What Is hCG?

As soon as you become pregnant, your body begins producing human chorionic gonadotropin (hCG), which can be found in the blood several days after conception. The hormone stimulates the corpus luteum to produce progesterone, which is essential for a developing embryo.

When a health care provider wants to confirm a pregnancy, they may order one or more quantitative hCG blood tests. These tests measure the amount of hCG in the pregnant person's blood.

An hCG level greater than 25 mIU/mL is enough to confirm a pregnancy with an at-home urine pregnancy test. People who aren't pregnant typically have hCG levels less than 5 mIU/mL.

hCG Levels Chart

The hCG levels chart below shows typical hCG numbers throughout pregnancy, which can vary widely from person to person and pregnancy to pregnancy.

Because every pregnancy is different, it's important not to compare your hCG levels to anyone else's (or even your own from a previous pregnancy). Try not to read too much into any single measurement. What really matters in early pregnancy is whether your hCG levels are increasing as expected.

Normal hCG Levels During Pregnancy

Typically, hCG production begins about 6 to 12 days after ovulation. The levels usually double every 29 to 53 hours, says Brennan Lang, MD, FACOG, an OB-GYN at Texas Children's Pavilion for Women.

This doubling trend continues until 8-10 weeks after implantation when hCG levels peak at around 90,000–100,000 mIU/mL. Then hCG levels start to plateau because the placenta takes over estrogen and progesterone production.

But here's the tricky part: Healthy hCG levels don't always double every two days. "The level of hCG detectable in blood tests increases rapidly in early pregnancy at a rate of about 35% to 200% or more every two days, which is a wide range of normal," says Maureen Baldwin, MD, MPH, an associate professor of obstetrics and gynecology at Oregon Health and Science University. That's why doctors don't pay much attention to individual hCG numbers; instead, they focus on hCG trends.

How To Measure Your hCG Levels

While home pregnancy tests alert you to the presence of hCG in your urine, they don't measure how much of the hormone is present. For that information, you'll need a blood test from a health care provider.

"Urine tests are very sensitive and will turn positive at low levels of usually 25, 50, or 100 mIU/mL, which can all detect pregnancy in the week after a missed period," says Dr. Baldwin. "Blood tests can give a concentration of the hormone and are pretty accurate, even from lab to lab."

At your first prenatal appointment, your health care provider may order a blood test to measure hCG levels and confirm your pregnancy. But they probably won't monitor hCG levels too closely at future appointments. That's because normal numbers vary greatly, and one test won't let you know if the baby is thriving.

Tracking hCG Levels by Week

Although hCG isn't usually monitored closely, your health care provider may track hCG if they're concerned about the health of your pregnancy or if you're showing signs of miscarriage like bleeding or cramping.

According to Dr. Baldwin, subsequent hCG blood tests, usually taken 48 hours apart, let doctors analyze trends in hCG levels. Rapidly rising, falling, or plateauing levels may require further testing.

After the pregnancy can be seen on ultrasound, providers will probably stop measuring hCG altogether. At this point, "the best measure of a normally-growing pregnancy is the monitoring of uterine size by your provider," says Dr. Baldwin.

"If a pelvic ultrasound shows a pregnancy inside the uterus with a heartbeat, there is no reason to keep checking hCG levels. They no longer predict the continuation of the pregnancy," adds Dr. Lang.

When hCG Levels Chart Signals a Problem

In instances where an initial hCG measurement is lower than expected or you're experiencing symptoms of miscarriage, a second test will most likely be ordered. When there's a decline in the level of hCG from the first test to the second test, this often means a miscarriage is likely, also known as an impending miscarriage.

Lower than average hCG levels may also indicate an ectopic pregnancy, which occurs outside of the uterus. Unfortunately, an ectopic pregnancy cannot be carried to term and requires immediate treatment with medication or surgery to end the pregnancy.

There's nothing you can do to increase your hCG levels when they're in decline. Typically, when an early miscarriage occurs, there's a chromosomal abnormality or another issue with the embryo that makes the pregnancy not viable, which is reflected in decreasing hCG levels.

On the other hand, if your hCG levels are higher than average, this can indicate a miscalculation of your conception date. High hCG levels can also signal a molar pregnancy (hydatidiform mole) or a pregnancy with multiples.