It is possible to get a false result, although as long as you’re not testing too soon you’ll usually get an accurate result. False negatives can happen when you test too early…or too late! As previously mentioned, levels of hCG taper off later in pregnancy, so you could be towards the tail end of a healthy pregnancy and still get a negative.
If you’ve miscalculated your cycle and think you’ve missed your period, you could end up testing too early even though you think it’s exactly the right time. It’s also a good idea to take your test first thing in the morning when you wake up, as the hCG concentration in your urine is at its highest then. When your pregnancy test is negative but your period still isn’t starting, it might be worth a chat with your GP.
It is unlikely that you will experience a false positive, but not impossible. This may happen if you’ve had a recent pregnancy loss or ended a pregnancy, and hCG is still detectable in your urine, or if you’re taking certain medications like hCG shots which stimulate egg release and are used in fertility treatment.
Other medications, including some anti-anxiety drugs and antihistamines, can also lead to a false positive. If you’re taking any of these medications and trying to conceive or suspect a false positive on a pregnancy test, consult your GP or pharmacist.
Sometimes illness or infection can cause your body to overproduce hCG, so in rare cases, medical conditions like urinary tract infections (UTIs) or certain types of cancer can cause false positives, particularly some ovarian cancers amongst others. If you’re experiencing unexplained symptoms along with a positive pregnancy test, it’s crucial to consult your GP or pharmacist.
It’s also possible if you wait longer than the time recommended in your pregnancy test’s leaflet that you will see an evaporation line where you would usually see the “test” line.