What Medications May Affect Pregnancy Test Results?

In this article, Dr. Gleaton shares how home pregnancy tests work, what medical conditions and medications could affect pregnancy test results, and when to talk to your doctor about a potential false positive result or chemical pregnancy.

By OBGYN and fertility expert Dr. Kenosha Gleaton

Taking a home pregnancy test can be a nerve-wracking experience, and you want to be confident when reading the results. We’ve already covered the most common questions in our guide to peeing on a stick (POAS) , but now it’s time to cover what medications and medical conditions could affect your pregnancy test results to ensure an accurate result.

How Medications Affect Pregnancy Test Results

To recap, pregnancy tests work by detecting the pregnancy hormone, human chorionic gonadotropin (hCG), in urine. If the urine pregnancy test detects a certain level of hCG, it will show a positive result. hCG is made when a fertilized egg implants in the uterus, usually around 10 days after conception, and increases every day in early pregnancy.¹

If you’re taking a medication that contains or affects hCG human chorionic gonadotropin production, it’s possible that you could receive a false pregnancy test result. This means you could receive a positive test without actually being pregnant, or (more rarely) a negative test when you are pregnant.

What Drugs Can Cause a False Positive Pregnancy Test?

Most medicines, including over-the-counter and prescription, should not affect the results of a home pregnancy test. But medicines that have the pregnancy hormone hCG in them may give a false positive test result. This includes some medicines given for infertility treatments—often called the “trigger shot” and sold under the brand names Novarel, Ovidrel, Pregnyl, and Profasi.²

What to Do If You Suspect Medication Is Affecting Pregnancy Test Results

If you suspect your medication may be affecting your pregnancy test results, you should consult with your doctor. Your doctor can run a blood test and perform a transvaginal ultrasound to give you a definite answer on whether or not you’re pregnant.

If you’re on medications for fertility treatments, it’s important you don’t interfere with your medication routine without supervision from your doctor.

When to Call Your Doctor

If you believe you’ve been getting multiple false positives or false negatives, you should see your doctor. This is especially important if you are participating in fertility treatments or are showing pregnancy symptoms, but receiving negative test results.

Some false pregnancy test results could be a result of a hormone imbalance, including PCOS, a chemical pregnancy or ectopic pregnancy, evaporation lines, and more.^3,4 It can also impact your mental health due to the stress and anxiety it can cause.⁵ Make sure you’re following your test instructions correctly to avoid any user error. We made sure our early-result pregnancy tests are simple and easy to use with jargon-free instructions to get the clear answer you need.

Follow Instructions and Know When to Seek Advice

It’s important to follow pregnancy test instructions exactly when taking a urine test, otherwise you could end up with a false positive or false negative result. If you’re following the instructions correctly and you’re still concerned that your results are incorrect, you should consult your doctor. Many fertility medications and occasionally some OTC or prescription drugs could cause a false positive pregnancy test result, but a blood pregnancy test and transvaginal ultrasound will help rule this out.

Sources:

1. Cleveland Clinic. Pregnancy Tests: How They Work, Types & Accuracy. Cleveland Clinic. Published 2021. https://my.clevelandclinic.org/health/articles/9703-pregnancy-tests 
2. Robles, MD. A. The Trigger Shot in IVF: 15 Questions You Need To Know - Alex Robles, MD. Alex Robles MD. Published October 20, 2021. Accessed July 31, 2023. https://alexroblesmd.com/trigger-shot/ 
3. Emery, MD. J. Causes of a False Positive Pregnancy Test. Cleveland Clinic. Published October 18, 2021. https://health.clevelandclinic.org/false-positive-pregnancy-test/ 
4. Coulam CB, Roussev R. Chemical Pregnancies: Immunologic and Ultrasonographic Studies. American Journal of Reproductive Immunology. 2002;48(5):323-328. doi:https://doi.org/10.1034/j.1600-0897.2002.01137.x 
5. Marteau TM, Cook R, Kidd J, et al. The psychological effects of false-positive results in prenatal screening for fetal abnormality: A prospective study. Prenatal Diagnosis. 1992;12(3):205-214. doi:https://doi.org/10.1002/pd.1970120309