What is HCG?

HCG (human chorionic gonadotropin) is often referred to as the pregnancy hormone because it is produced by cells produced in the placenta that nourish the egg after fertilization and attach to the uterine wall. Levels can be first detected with a blood test about 11 days after conception and about 12 to 14 days after conception with a urinalysis.

Typically, hCG levels double every 72 hours. The level peaks during the first 8-11 weeks of pregnancy, then decreases and stabilizes until the end of pregnancy.

What you need to know about hCG levels:

As pregnancy progresses and hCG levels increase, the time it takes to double can increase to about every 96 hours.
Caution should be taken when using too many hCG numbers. A normal pregnancy can have low hCG levels and result in a perfectly healthy baby. Ultrasound results after 5-6 weeks of pregnancy are much more accurate than when using hCG numbers.
HCG levels below 5 mIU/ml are considered negative in pregnancy, and levels above 25 mIU/ml are considered positive in pregnancy.
An hCG level between 6 and 24 mIU/mL is considered a gray area and you will likely need to be retested to see if your level rises to confirm pregnancy.
The hCG hormone is measured in milli-international units per milliliter (mIU/mL).
Transvaginal ultrasound should show at least one ovum after the hCG level reaches 1000-2000 mIU / ml. Since levels can vary greatly and the date of conception can be erroneous, an ultrasound diagnosis cannot be made until the hCG level reaches at least 2000 mIU/ml.
One reading is not enough for most diagnostics. When the question arises about the state of pregnancy, a more accurate assessment of the situation is given by several hCG tests done at intervals of several days.
HCG levels should not be used to determine the date of pregnancy as these numbers can vary greatly.
There are two common types of hCG tests. A qualitative test determines if hCG is present in the blood. A quantitative (or beta) test measures the amount of hCG actually present in the blood.

What does low hCG mean?

A low hCG level can mean several things and should be rechecked within 48-72 hours to see how the level changes. A low level may indicate:

Miscalculation of pregnancy dating
Possible miscarriage or blighted ovum
Ectopic pregnancy

Is high hCG levels bad?

A high hCG level can also mean a number of things and should be re-tested within 48-72 hours to assess changes in levels. A high level may indicate:

Miscalculation of pregnancy dating
Molar pregnancy
Multiple pregnancies

Should I check my hCG levels regularly?

Doctors rarely check your hCG levels unless you have signs of a potential problem.

Your doctor may recheck your levels if you have bleeding, severe cramps, or a history of miscarriage.

What can I expect after pregnancy loss?

Most women can expect their levels to return to non-pregnant levels about 4 to 6 weeks after an abortion.

This can differ in how the loss occurred and how high the levels are at the time of the loss.

Doctors usually continue to check hCG levels after a pregnancy is terminated to make sure it returns to <5.0.

What can affect my hCG levels?

If you get a positive test result, you are most likely pregnant. False positives are extremely rare. However, some conditions can lead to a false positive result, such as some cancers and early miscarriage. Some antibodies can also interfere with test results.

Medications containing hCG can also affect hCG levels.

These drugs are often used in the treatment of infertility and your doctor should let you know how they may affect the test.

All other medications, such as antibiotics, painkillers, birth control pills, or other hormonal medications, should not interfere with the hCG test.