What Does a Faint Line On a Pregnancy Test Mean?

Taking a pregnancy test can be nerve-wracking regardless of what outcome a person is hoping for.

Whether someone is hoping for a negative or positive result, everyone wants a definitive, clear answer from their at-home pregnancy test. 

However, sometimes the results can be hard to read, particularly if a faint line appears.

Many people find themselves wondering “what does a faint line mean on a pregnancy test?”

How Do Pregnancy Tests Work?

At-home pregnancy tests can provide a very accurate result virtually all of the time when used as directed.

Pregnancy tests measure the amount of a hormone called human chorionic gonadotropin, or hCG, in the urine.

This hormone, sometimes referred to as the pregnancy hormone, increases significantly during early pregnancy.

The concentration of hCG increases at conception, with levels in the urine and blood doubling every 72 hours during the first 8 to 12 weeks of pregnancy.

When using an at-home pregnancy test, the test is placed in the urine stream or in a container filled with urine for about seven to ten seconds, allowing the test to become fully saturated.

Then, the test is placed horizontally on a flat surface for three to five minutes, after which the results can be read. 

Most pregnancy tests include one line, known as the control line, that will appear regardless of whether or not a woman is pregnant.

The appearance of a second line, known as the test line, indicates a positive test result. Other pregnancy tests may produce digital readouts that simply say “pregnant” or “not pregnant.”

Blood can also be tested for the hormone human chorionic gonadotropin.

This method can yield results slightly earlier than a urine test.

What Does a Faint Line on a Pregnancy Test Mean?

A faint line on a pregnancy test can be caused by one of three things: a positive test result, evaporation lines, or a chemical pregnancy.

Positive Test Result

A faint line on a pregnancy test often indicates a positive test result, meaning the person is pregnant. 

As we mentioned above, pregnancy tests measure the amount of hCG in a person’s urine.

The body starts to produce more hCG as soon as conception occurs, with the amount of hCG in the body doubling about every 72 hours for the first 8 to 12 weeks of pregnancy. 

A faint positive pregnancy test line can indicate that hCG is present in the body at the lower end of elevated levels, meaning the person is early in their pregnancy. 

If you are trying to get pregnant or think you might be pregnant and receive a faint line on a pregnancy test, try waiting a few days and taking another test to see if the line shows up darker. 

If it does, that’s a sign that your body is continuing to hCG and you are pregnant. Because the tests are more accurate as hCG builds up in the bloodstream, it is recommended that women wait one week after a missed period before testing. 

Evaporation Line 

A faint line on a non-digital test can also be caused by an evaporation line. Also known as the shortened “evap line,” this faint line appears as the urine evaporates from the absorbent portion of the pregnancy test, sometimes leaving behind a faint line. 

When a faint positive line on a pregnancy test is caused by an evaporation line, the person is not pregnant and the test result should reflect as negative. 

It can be challenging to tell whether a faint line on a pregnancy test is a positive pregnancy test result in early pregnancy or an evaporation line.

However, the best way to be sure is to follow the instructions on the test packaging carefully. 

If a faint line appears on the pregnancy test window within the recommended time frame for checking the test (typically 3 to 5 minutes), the result is likely positive.

However, if the person does not check the results for 10 or more minutes after the test has been taken, the faint line could be caused by an evaporation line and may be a false positive pregnancy test.

If you’re not sure whether or not a faint line on a pregnancy test is caused by a positive test result or an evaporation line, resulting in a false positive result, wait another two to three days before taking another test.

This gives the body more time to produce hCG, which will produce a clearer positive result if you are pregnant. You can also opt for a digital pregnancy test.

Chemical Pregnancy and Other Pregnancy Losses

A faint line on a pregnancy test can also be a sign of a chemical pregnancy. A chemical pregnancy (sometimes also mimicked by an ectopic pregnancy), is a pregnancy that ends in early miscarriage before the fifth week of pregnancy.

In these cases, an egg has been fertilized but may fail to implant properly or develop as it should. 

Many women who experience a chemical pregnancy do not know they are pregnant, as it may be too early to experience notable pregnancy symptoms. 

As with normal pregnancies, a chemical pregnancy results in the production of hCG from the time of conception.

Even if a miscarriage occurs, some hCG often remains in the body for several weeks after this early pregnancy loss, which can cause a faint line on a pregnancy test. 

However, the pregnancy is not viable and has already ended. 

Women can also see a faint line on a pregnancy test if they have certain medical conditions or experienced a recent pregnancy loss such as a later miscarriage or abortion. The levels of hCG in the body take several weeks to subside.

The Bottom Line

A faint line on a pregnancy test can be caused by a positive test result, evaporation lines, or a chemical pregnancy. 

The best way to determine whether or not you are pregnant is to wait at least one week after a missed period before taking a test and follow the directions on the packaging exactly as instructed. 

When in doubt, you can always ask your OB/GYN or primary healthcare provider to run a blood test for the most accurate results.

References and Sources:

Chemical Pregnancy: Causes, Symptoms & Treatment | Cleveland Clinic 

hCG Levels | The American Pregnancy Association 

Pregnancy Tests: How They Work, Types & Accuracy | Cleveland Clinic