Imagine this: you’ve been trying to get pregnant but missed your period, so you take a pregnancy test to see if this is your last month. But when it comes time to check the results, instead of a clear pregnancy line you see a faint line that makes you question the reliability of this pregnancy test. Am I pregnant?
If you’ve ever gotten a faint line on a pregnancy test, it’s natural to feel frustrated and anxious, but don’t worry, we have the answers. We spoke to experts to find out what a faint line on a pregnancy test means and when you should see a doctor.
So what do lines on a pregnancy test mean?
If you’re using a home pregnancy test kit that displays a line in the result window, you should see the first line right after the kit comes into contact with your urine sample. This first line is called the control line, and it’s there to show you that the test is working properly. If you don’t see the control line, you should discard the test as it may not give accurate results.
The second line you’ll see on a home pregnancy test kit is called the test line. This line only appears if the amount of human chorionic gonadotropin (hCG) in your urine is high enough to be detected, notes Kate Uber, PhD, MPH, CNM, FACNM, resident associate professor and director of the Midwifery Program at the University of Nevada, Las Vegas.
In addition to the traditional pregnancy test that shows two lines, there are many other types of home pregnancy tests. Some use a plus sign to indicate pregnancy, and there may also be digital versions.
What causes a faint line on a pregnancy test?
If you’ve taken a home pregnancy test and seen a faint line, you may be worried or confused. Here are some reasons why a faint line might appear on a pregnancy test:
You are pregnant, but there is not enough hCG in your urine yet
A faint line could mean that your urine sample was very dilute or that you were in the early stages of pregnancy and may have contained just enough hCG to make the test positive, says Uber. Keep in mind that hCG increases exponentially when you’re pregnant, so even if you see a faint line now, it’s likely to become clearer if you test again in a day or two.
Dr Oliver Seejoe Hoang, laboratory director at Innovative Health Diagnostics, added that a single line, no matter how faint, usually indicates a positive result. “However, every test is different, so it’s important to follow the instructions exactly. If you’re unsure, it’s best to repeat the test.”
You are not pregnant and the faint line is an evaporation line.
If you wait too long for your results, the urine on the pregnancy test may dry out, leaving a faint line called an evaporation line. “Evaporation lines are grey in colour and can appear around 10 minutes after taking the test,” explains Dan Nayot, MD, BSc, MSc, FRCSC, GREI, reproductive endocrinologist, infertility specialist and chief medical advisor at Bird & Be.
If you’re not sure if you followed the kit’s instructions correctly, Woeber suggests waiting a few days and then testing again.
Other reasons for a faint line on a pregnancy test
Other reasons for a faint line on a pregnancy test include a chemical pregnancy, a very early miscarriage, certain infertility conditions, and certain fertility/IVF medications that may affect the results. Research has also shown that premenopausal women may have higher levels of hCG in their bodies. Meanwhile, postmenopausal people may have higher hCG levels that can cause a positive pregnancy test even if they’re not pregnant, Dr. Nayot points out.
If you’re unsure of your results, it’s important to continue testing, either at home or possibly with your healthcare provider. “It’s best to also measure your serum (blood) hCG levels for comparison,” says Shvetha Murthy Zarek, MD, FACOG, fertility specialist and IVF medical director at Oma Fertility in St. Louis, advised. “Depending on these results, your doctor may order another hCG blood test or recommend an ultrasound to monitor hCG trends.”
Can pregnancy tests be wrong?
Unfortunately, home pregnancy tests can produce both false positive and false negative results. For example, if you’ve had a miscarriage but still have hCG in your body, you could get a false positive result, says Dr. Nayot, adding, “If you’re undergoing fertility treatment and are taking certain fertility medications, you could also get a positive result.”
There’s also an element of user error: Not placing the test strip in the urine long enough or leaving the test strip in the urine for too long can alter the results. “It’s important to read the instructions and follow the specific steps given to perform the test,” adds Dr. Nayot.
False negative results are usually caused by taking a pregnancy test too early. A pregnancy test can give you a false negative result if your hCG levels aren’t high enough to produce a positive result. “People who think they’re pregnant but get a negative test can try again in a few days,” advises Dr. Woerber, adding that the best time to use a home pregnancy test is in the morning. “By that time, hCG levels will be higher and the test will be easier to detect.”
What you need to know about blood tests
Blood is a much more reliable way to monitor hCG levels because its composition remains fairly constant, making it easier to track changes in chemicals like hCG. Therefore, blood tests that measure hCG over several days are a much more reliable way to monitor hCG levels than urine tests.
A blood test can detect pregnancy 9 to 10 days after ovulation. However, doctors don’t recommend blood tests until your expected period, and only if there’s a medical need for it.
When to contact your healthcare provider
If you see a faint line on your pregnancy test, take a deep breath first. There are a lot of factors that can contribute to these puzzling results, so a good first step is to try again in a few days and see how the information changes.
That said, if you continue to see that faint line, it may be time to see a healthcare provider. “A blood test can definitively tell you if you’re pregnant or not,” Dr. Nayot explains, adding that further testing can also shed light on why your results were inconclusive in the first place.
Additional reporting by Krissi Danielsson.
