You suspect you’re pregnant and you have taken a home pregnancy test, but suddenly your anticipation turns to confusion when you spot a very faint line on the test. What does it mean? Find out why your test line may be faint and whether you are pregnant or not.
- A pregnancy test detects the presence of the hCG ‘pregnancy’ hormone.
- HCG is normally only present in your body if you are pregnant.
- Any positive line, no matter how faint, means your result is pregnant.
- Levels of hCG in your body will increase over the course of your pregnancy.
- If you test early, your hCG levels may be still be low and you’ll see a faint positive line.
- You can avoid getting faint lines by using a digital test, use the first urine in the morning if testing early, and don’t drink too much liquid before testing.
If you see a positive line, you’re pregnant
A pregnancy test checks for the presence of a hormone known as hCG (human Chorionic Gonadotrophin). This is often called ‘the pregnancy hormone’ because it is usually only present in your body when you are pregnant. As your pregnancy progresses, levels of hCG will go up, making it easier for tests to detect. Some pregnancy tests, like the Clearblue Digital Pregnancy Test, will give you a clear answer in words like ‘Pregnant’ or ‘Not Pregnant’, however, many tests will show two lines if you’re pregnant.
If the test has worked – and you are using a visual test – you will always see the ‘control line’– but if you’re pregnant, another line will also develop. Sometimes it’s easy to say whether the pregnancy test is positive or not, but sometimes this other line can be very faint. If you see a positive line , even if it’s faint, the simple answer is: Yes, you are almost certainly pregnant.
What causes faint positive lines on a pregnancy test?
The strength of the positive test line depends on how much hCG is in your urine. If the line is faint, it usually means that the hCG level is low. One reason why hCG levels may be low could be because you’re still very early into your pregnancy. Some very sensitive pregnancy test kits can detect pregnancy as early as 6 days before your missed period (5 days before you expect your period), however the levels of hCG this early are so low that you can expect any line to be faint. As your pregnancy progresses, the levels of hCG will rise, so if you choose to test again, you will likely see a much stronger positive line.
You can see how your hCG levels rise in your urine over the course of early pregnancy in the graph below.
Rise of pregnancy hormone (hCG) in early pregnancy
Adapted from: Gnoth C. and Johnson S. Strips of Hope: Accuracy of Home Pregnancy Tests and New Developments. GeburtshilfeFrauenheilkd 2014;74(7):661–669.
Another reason you may only see a faint positive is because you’ve drunk too much liquid. Drinking a lot of water or other beverage before taking a pregnancy test may help you produce a urine sample more quickly, but it will dilute the concentration of any hCG. Drinking a lot of liquid before testing can leave you with a faint positive line, or if you’re testing early, even a negative result.
It may be easy to think a faint line is a false positive, but it’s very, very rare to get a false positive result. You can read more about false positive pregnancy test results here.
What does a faint line look like?
Each pregnancy test is different, with some brands using a red dye and others, like Clearblue, a blue dye. For a red dye test, a faint line will look light pink, whereas a blue dye test will produce a light blue line. See images below to get an idea of what a faint line can look like.
How can I avoid getting faint lines on my pregnancy test?
You can avoid the uncertainty of faint lines if you:
- Go digital. Use a digital pregnancy test that spells the result out for you, so you no longer need to try to read faint lines.
- Follow the manufacturer’s instructions for the test. This is really important. Different tests will have different sensitivities (what level of hormone they can detect) and some may be suitable for testing before your missed period whereas others may not be. If you want to test early, make sure you use a test designed for the job.
- Do the test first thing in the morning. if you’re testing early, take the test first thing in the morning when your hCG levels are more concentrated.
- Don’t drink too much liquid. Drinking a lot of liquid, including water, before testing can dilute your hCG levels.
If you do see faint lines and you’re still not sure whether or not you are pregnant, you might wish to test again in a few days’ time when your hCG levels may be higher. If you’re still not sure, see your doctor.
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Can a positive result be wrong?
False positives are incredibly rare. Find out what can cause them and why you may get a negative result after testing positive.