What medications can cause a false positive pregnancy test?
Some medications can cause a false positive pregnancy test result.
Home pregnancy tests measure levels of human chorionic gonadotropin (hCG) hormone in urine. Taking any medication that contains hCG can cause a false-positive result.
Drugs that contain the hCG hormone aimed at boosting fertility may impact pregnancy test results. These may include:
Other drugs that may cause a false positive pregnancy test include:
- Antipsychotics often used to treat schizophrenia, such as perphenazine, prochlorperazine, chlorpromazine, trifluoperazine, thioridazine and thiothixene
- The anti-seizure/anticonvulsant drug carbamazepine used for epilepsy, facial nerve pain and bipolar disorder
- Progestin-only birth control pills, including:
- Anti-nausea drugs, including prochlorperazine, perphenazine, chlorpromazine and promethazine
- Sedatives that are used before and after surgery or during labor, such as promethazine
- Antihistamines such as promethazine
- Anti-anxiety medications such as prochlorperazine and trifluoperazine
Importantly, most medicines will not affect the results of a home pregnancy test. Alcohol and illicit drugs also don’t affect pregnancy test results.
Other factors that can cause inaccurate results on pregnancy tests may include:
- Incorrect use of the test
- Testing too early
- Use of an expired test
- Certain cancers
- Early miscarriage
References
- American Pregnancy Association. Fertility Medications. Available at: https://americanpregnancy.org/getting-pregnant/fertility-medications/. [Accessed February 12, 2022].
- U.S. National Library of Medicine MedlinePlus. Perphenazine. February 15, 2018. Available at: https://medlineplus.gov/druginfo/meds/a682165.html. [Accessed February 12, 2022].
- U.S. National Library of Medicine MedlinePlus. Prochlorperazine. February 15, 2018. Available at: https://medlineplus.gov/druginfo/meds/a682116.html. [Accessed February 12, 2022].
- U.S. National Library of Medicine MedlinePlus. Chlorpromazine. July 15, 2017. Available at: https://medlineplus.gov/druginfo/meds/a682040.html. [Accessed February 12, 2022].
- U.S. National Library of Medicine MedlinePlus. Trifluoperazine. July 15, 2017. Available at: https://medlineplus.gov/druginfo/meds/a682121.html. [Accessed February 12, 2022].
- U.S. National Library of Medicine MedlinePlus. Thioridazine. May 15, 2017. Available at: https://medlineplus.gov/druginfo/meds/a682119.html. [Accessed February 12, 2022].
- U.S. National Library of Medicine MedlinePlus. Thiothixene. July 15, 2017. Available at: https://medlineplus.gov/druginfo/meds/a682867.html. [Accessed February 12, 2022].
- U.S. National Library of Medicine MedlinePlus. Carbamazepine. May 15, 2020. Available at: https://medlineplus.gov/druginfo/meds/a682237.html. [Accessed February 12, 2022].
- U.S. National Library of Medicine MedlinePlus. Progestin-Only (norethindrone) Oral Contraceptives. March 15, 2021. Available at: https://medlineplus.gov/ency/article/003432.htm. [Accessed February 12, 2022].
- U.S. National Library of Medicine MedlinePlus. Promethazine. June 15, 2017. Available at: https://medlineplus.gov/druginfo/meds/a682284.html. [Accessed February 12, 2022].
- Office on Women’s Health. Pregnancy Tests. January 31, 2019. Available at: https://www.womenshealth.gov/a-z-topics/pregnancy-tests. [Accessed February 12, 2022].
