When taking a pregnancy test, it’s important to have confidence in its accuracy.
Whether you’re eager to start a family or not ready, the test results must be reliable.
However, if you have a urinary tract infection (UTI) at the time of testing, you may be unsure about how that could impact the results.
In this case, it’s important to understand the potential effects of a UTI on a pregnancy test result.
What is a UTI?
A UTI is an infection in the urinary system, which includes the kidneys, ureters, bladder, and urethra.
UTIs are very common in women because of their lower urinary system anatomy and its closeness to their reproductive organs, making them more prone to getting infections than men.
UTIs can sometimes be asymptomatic, but when symptoms do occur, they may include:
- A persistent and intense urge to urinate
- A burning sensation while urinating
- Frequent urination with only small amounts of urine passed each time
- Cloudy urine or urine that appears reddish, pinkish, or dark, indicating the presence of blood
- Foul-smelling urine
- Pelvic pain in women, especially in the central pelvic region and around the pubic bone area
How Do Pregnancy Tests Work?
A pregnancy test that you can buy at a store is usually a urine test that detects the hormone human chorionic gonadotropin, or hCG, which helps maintain pregnancy by promoting the release of progesterone.
HCG is produced when a fertilized egg attaches to the uterus, typically around 10 days after conception when the sperm fertilizes the egg.
It can be detected in both blood and urine. As the pregnancy progresses, the level of hCG in the body increases each day rapidly.
Therefore, taking a home pregnancy test too soon after implantation may not detect the pregnancy due to low levels of hCG.
In this case, taking another pregnancy test in a few days is recommended.
Most pregnancy tests show a positive result with two parallel colored lines or a plus sign.
Some tests can be held directly in the urine stream, while others need to be dipped into a container. HCG is most concentrated in the morning.
Therefore, a pregnancy test should be done in the morning if possible.
Accuracy of Home Pregnancy Tests
Home pregnancy tests are said to be up to 99% accurate, but this accuracy depends on how you use them when you use them, and the brand of test you choose.
- It’s important to check the expiration date and follow the instructions carefully. Waiting up to 10 minutes before checking the results can give the most accurate result.
- The amount of pregnancy hormone in your urine increases with time, so testing after a missed period can boost the accuracy. However, the timing of implantation varies, so some women may only get accurate results later.
- Additionally, some tests are more sensitive than others, so it’s a good idea to talk to a pharmacist about which brand may be best for you.
Can UTIs Affect The Results of a Pregnancy Tests?
Rarely, but UTIs can affect pregnancy tests.
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How Can a UTI Cause a False Positive Pregnancy Test?
A false positive pregnancy test occurs when a woman is not pregnant but the test shows a positive result.
Getting a false positive pregnancy test can upset people and cause delays in medical tests for other health problems.
Reasons can be a chemical pregnancy, recent miscarriage or abortion, user error, medications, malignancies, and so on.
UTIs, kidney diseases that cause blood or white blood cells, and nitrites in the urine can also cause a pregnancy test to be positive.
Such a case in a 28-year-old woman was reported, who had a delayed diagnosis of kidney inflammation (pyelonephritis).
Another study found that both cancerous and non-cancerous diseases affecting the urinary tract, such as UTIs, can lead to an increase in the production of hCG, therefore, to a positive test.
How Can a UTI Cause a False Negative Pregnancy Test?
A false negative pregnancy test occurs when a woman is pregnant but the test shows a negative result.
UTIs can cause difficulty or pain in controlling urine flow in some women, impacting the accuracy of at-home pregnancy tests.
Since these tests measure the level of hCG in the urine, too much or too little urine on the test strip can affect the results.
If you’re concerned about excessive urine on the test strip, you can collect urine in a cup and dip the test strip into the cup for the recommended amount of time.
If you cannot collect enough urine on the test strip, it may result in a negative pregnancy test.
Medical professionals advise that consuming a large amount of water can be beneficial in managing UTI symptoms by eliminating the bacteria causing the infection from the body.
However, this can dilute the urine and yield an inaccurate negative result in a pregnancy test.
This is particularly common during the initial stages of pregnancy when the levels of hCG are low and might be difficult to identify.
Can UTI Medications Affect Pregnancy Tests?
If you have a UTI, your doctor would typically prescribe antibiotics to treat the infection.
Fortunately, antibiotics have not been found to affect the accuracy of home pregnancy tests.
Therefore, it is implausible that taking antibiotics for a UTI would cause a false positive or negative result on a pregnancy test.
The use of over-the-counter UTI medications, such as AZOs, can make it challenging to interpret the results of a pregnancy test because the dye present in these medications can soothe the urinary tract lining and stain the urine an orange-red or blue color.
This dye can make it hard to read the result window of the pregnancy test. So it is clear that the presence of a coloring substance in your urine can affect the accuracy of the result of an at-home pregnancy test.
What to Do Next?
- If your home pregnancy test is positive, see a healthcare provider for confirmation, and start prenatal care as soon as possible.
- If your home pregnancy test is negative but your period doesn’t start, wait a few days or a week, and take the test again. Repeat this process if necessary.
- If you continue to have negative test results but miss your period or suspect that you might be pregnant, see a healthcare provider. They can perform a more accurate blood test and help identify any underlying health issues that may be affecting your menstrual cycle.
Remember, if a UTI spreads to the kidneys, it can cause severe health problems. So, getting checked out if you experience UTI symptoms is always a good idea, even if you’re not taking a pregnancy test.
References
- https://www.mayoclinic.org/diseases-conditions/urinary-tract-infection/symptoms-causes/syc-20353447
- K. Czajkowski, M. Broś-Konopielko, and J. Teliga-Czajkowska, “Urinary tract infection in women,” Przegla̜d Menopauzalny = Menopause Rev., vol. 20, no. 1, p. 40, 2021, doi: 10.5114/PM.2021.105382.
- “Schwangerschaftstest weist nach, ob Schwangerschaft vorliegt.”
- https://www.vitabook.de/gesundheitslexikon/schwangerschaftstest.php
- “Pregnancy tests | Office on Women’s Health.” https://www.womenshealth.gov/a-z-topics/pregnancy-tests
- https://www.healthline.com/health/pregnancy/false-positive-pregnancy-test “Pregnancy test (beta-hCG).
- https://www.gloshospitals.nhs.uk/our-services/services-we-offer/pathology/tests-and-investigations/pregnancy-test-beta-hcg/
- R. Mital, M. Forster, A. Alloghbi, and A. Kayyali, “A Case of a False-Positive Urine Pregnancy Test and Delayed Diagnosis of Obstructive Pyelonephritis,” Am. J. Case Rep., vol. 21, pp. e920440-1, 2020, doi: 10.12659/AJCR.920440.
- A. B. Halim, O. El-Ahmady, M. Barakat, A. M. El-Zayat, and Daw, “Urinary beta-HCG in benign and malignant urinary tract diseases,” Dis. Markers, vol. 12, no. 2, pp. 109–115, 1995, doi: 10.1155/1994/179287.
- https://www.webmd.com/drugs/2/drug-77838/azo-oral/details
- https://www.mayoclinic.org/healthy-lifestyle/getting-pregnant/in-depth/home-pregnancy-tests/art-20047940
Nazeli Gevorgyan studied at Yerevan State Medical University and is an Obstetrics/Gynecology resident
