hCG Levels by Week: Normal Ranges, Doubling Time and What the Numbers Mean

What are normal hCG levels by week?

Normal hCG levels span a very wide range in each week of early pregnancy: Cleveland Clinic lists 5 to 426 mIU/mL at 4 weeks after the last menstrual period, 18 to 7,340 mIU/mL at 5 weeks and 1,080 to 56,500 mIU/mL at 6 weeks. Its chart shows hCG rising quickly through the first trimester, then falling.

MedlinePlus publishes different ranges, such as 217 to 8,245 mIU/mL at 5 weeks and 31,366 to 149,094 mIU/mL at 8 weeks, and says normal ranges may vary slightly among laboratories. Cleveland Clinic calls its chart just a guide, says healthy pregnancies may have lower-than-average levels, and says how the number changes matters more than the number itself.

Cleveland Clinic says hCG peaks around 10 weeks of pregnancy and then gradually falls until birth. MedlinePlus describes the same pattern: a rapid rise in the first trimester, then a slight decline.

What is a beta hCG test?

A beta hCG test is a blood test that measures the exact amount of hCG in your blood; the Office on Women's Health says it is also called a quantitative blood test. The qualitative version, the Office on Women's Health says, only checks whether hCG is present, and Cleveland Clinic notes that a home urine test likewise shows that hCG is there without showing how high it is.

MedlinePlus says a quantitative test can help estimate how far along a pregnancy is and help diagnose an ectopic pregnancy, a molar pregnancy or a possible miscarriage. Cleveland Clinic says hCG is not checked routinely during pregnancy, and may be measured in the first trimester if there is a concern about how the pregnancy is progressing.

MedlinePlus says hCG appears in the blood and urine as early as 10 days after conception, and the Office on Women's Health says the quantitative test can find even tiny amounts. Cleveland Clinic says a level above 25 mIU/mL usually means you are pregnant, though it is not a guarantee, and MedlinePlus gives under 5 mIU/mL as normal for women who are not pregnant. When to take a pregnancy test covers home tests.

How fast should hCG levels double?

The Office on Women's Health says hCG levels should double every 48 hours in early pregnancy, while Cleveland Clinic and MedlinePlus both say hCG almost doubles every three days. Cleveland Clinic puts that fast rise in the first 8 to 10 weeks. It also says providers sometimes look at how quickly hCG rises in early pregnancy to confirm that the pregnancy is progressing.

Research on women with early pain or bleeding shows how much the rise varies. A 2004 study of 287 women in Obstetrics & Gynecology, all later confirmed to have an ongoing pregnancy in the uterus, found a median rise of 124% over 2 days, while the slowest rise was 53%. The authors concluded that hCG can rise more slowly in a viable pregnancy than earlier studies reported.

A 2016 study in the same journal, of 285 women, found that the slowest expected rise depends on the starting level. For a first result under 1,500 mIU/mL, the slowest expected 2-day rise was 49%; it was 40% for a result between 1,500 and 3,000, and 33% above 3,000.

What does a low hCG level mean?

A low hCG level does not diagnose anything on its own, Cleveland Clinic says; it is a tool for spotting possible problems. It lists the possible causes of a low or falling level as a blighted ovum, a miscarriage, an ectopic pregnancy, or simply not knowing the date of your last period.

When a level is low for the stage of pregnancy, Cleveland Clinic says your provider will recheck it in two or three days or do an ultrasound, which can confirm the pregnancy and measure how far along it is. ACOG says a low or decreasing hCG level can mean a pregnancy loss, and that several ultrasound exams and hCG tests may be needed before that is confirmed. Miscarriage risk by week gives the numbers for each stage.

What does a high hCG level mean?

A high hCG level can mean the pregnancy is further along than you thought, or that you are carrying twins, triplets or more, according to Cleveland Clinic. Both Cleveland Clinic and MedlinePlus also list a molar pregnancy, an abnormal growth of tissue in the uterus that MedlinePlus says must be removed.

MedlinePlus says the symptoms of a molar pregnancy can include abnormal vaginal bleeding, pain in the belly or pelvis, high blood pressure and severe nausea.

When should you call your doctor or midwife?

Cleveland Clinic advises contacting your provider with any questions about your hCG results. Call your doctor or midwife if you have any of these symptoms, which ACOG and the NHS list:

• Vaginal spotting or bleeding, with or without pain. ACOG says to contact your OB-GYN right away if the bleeding is heavy or comes with pain like period cramps.
• A gush of fluid from the vagina, even without pain or bleeding, or passing tissue (ACOG).
• Pain in your belly, typically low down on one side, or pain at the tip of your shoulder, which the NHS lists among the symptoms of an ectopic pregnancy.
• Pain or pressure in your bottom when you poo, pain when you pee, or diarrhea, which the NHS also lists as possible ectopic symptoms.