hCG Levels and Miscarriage

In the first trimester of a normal pregnancy, levels of human chorionic gonadotropin, a pregnancy hormone commonly known as hCG, increase over time. Usually, hCG levels double every two to three days in early pregnancy.

hCG is made by placental cells that provide nourishment to the egg after it has been fertilized and attaches to the uterine wall. It is the same hormone that home pregnancy tests can detect in urine about 12 to 14 days after conception. Blood tests are more sensitive and can detect the hormone as early as 11 days after conception.

In most healthy pregnancies, hCG levels, measured in milli-international units per milliliter (mIU/mL), will double about every 72 hours, which is why physicians will order two consecutive tests taken two to three days apart. The hormone will reach its peak in the first 8 to 11 weeks of pregnancy, after which it will decline and level off for the rest of the pregnancy.

Normal hCG Levels

Levels of hCG can vary dramatically between women and from one pregnancy to the next in the same woman. Generally, an hCG level of less than 5 mIU/mL means a woman is not pregnant while anything 25 mIU/mL or higher indicates pregnancy.

While the below ranges give an idea of what is considered normal, the results of one hCG blood test mean very little. Rather, the change in the level between two consecutive tests done 2 to 3 days apart is much more telling of how pregnancy may progress.

What Does a Low hCG Level Mean?

Women whose hCG level falls over a period of two to three days in the first trimester in two quantitative hCG blood tests are often advised that this means an impending miscarriage. This is especially true for women with other miscarriage symptoms, such as vaginal bleeding during pregnancy.

However, falling hCG levels are not a definitive sign of miscarriage, even with bleeding. Sometimes, hCG levels drop, but then rise again and the pregnancy continues normally. Although this is not common, it can happen.

Decreasing hCG levels later in pregnancy, such as the second and third trimester, are probably not a cause for concern. Most doctors do not check hCG levels for purposes of evaluating the progress of a pregnancy after the first trimester, although single hCG levels might be checked as a part of the AFP prenatal screening test.

What Happens Next

If hCG levels are dropping and ultrasound shows that the pregnancy has been lost, there are a few different options. Your doctor may:

• Prescribe medicines that can speed the process of miscarriage
• Recommend a surgical procedure such as a D&C
• Suggest that you "watch and wait," allowing the miscarriage to proceed

hCG Levels After Miscarriage

After a pregnancy loss, hCG levels will return to a non-pregnant range (less than 5 mIU/mL) between four and six weeks later. However, the exact length of time it takes for your hCG levels to lower depends on a variety of factors, including how the loss occurred (spontaneous miscarriage or dilation & curettage) and how high your levels were when you miscarried.

It is typical for physicians to continue to test hCG levels after a miscarriage, because levels that don’t drop may require medical follow-up. In some cases, elevated hCG levels following a miscarriage can indicate a molar pregnancy, which needs to be treated.

A Word From Verywell

Knowing that your hCG levels are dropping can be very stressful, even if the pregnancy is viable. Stay in touch with your healthcare provider so that you can be well informed, and seek out support from your partner or another person that you feel comfortable with. Some women benefit from counseling too. There's no shame in needing help and asking for it.