Birth Control Effects on Pregnancy Tests

by Michelle Powell-Smith

Pregnancy tests are an effective, affordable and convenient way to determine you are pregnant. Home pregnancy tests require nothing more than a urine sample, while your doctor may use a urine or blood test. If you are taking hormonal birth control, like the pill, Depo-Provera, or the NuvaRing, you may have questions about the effectiveness of home tests if you are concerned about an unplanned pregnancy.

Function

Pregnancy tests recognize the presence of hCG or human chorionic gonadotropin produced during pregnancy. Some urine tests may detect levels as low as 20 million International Units of hCG, reports Early-Pregnancy-Tests.com. Other pregnancy tests are less sensitive and may not recognize pregnancy until 25 to 50 mIU of hCG are present, according to Medline Plus. Blood tests quantify the amount of hCG and can help to determine whether a pregnancy is viable.

Significance

Even if you use contraception, you may occasionally have a late period. Late menstrual periods can be the result of hormonal irregularities, stress or pregnancy. You can reduce worry by testing for pregnancy if your period is late. Whether you opt for hormonal or barrier methods of birth control, none contain hCG or impact the results of a home pregnancy test or one in the doctor's office.

Time Frame

If you take birth control pills, use the patch or the NuvaRing, you should expect your period during the week off, unless you opt for continuous use. If you miss your period, you should take a pregnancy test to rule out the possibility of pregnancy. Some forms of birth control, including Depo-Provera, continuous birth control pills and the Mirena IUD may reduce or eliminate periods altogether. While pregnancy is unlikely, you can use a home pregnancy test if you have reason to suspect that your birth control has failed.

Misconceptions

While some hormonal birth control methods may cause side effects similar to early pregnancy, including breast tenderness or nausea, they do not cause your body to produce hCG. HCG is produced during pregnancy, or it may indicate an illness requiring medical care if you are not pregnant. If you do get a positive pregnancy test while taking birth control, visit your health care provider to confirm your pregnancy and discuss your options.

Warning

While false positives on home pregnancy tests are unlikely, false negatives are more common. Test directly after waking up with first-morning urine for the most accurate result, particularly early in pregnancy. If you get a negative result but you continue to suspect pregnancy, wait a few days and retest. If you have opted for birth control that can stop menstruation, there is likely no need for concern. If you do not start your period during the week off your birth control pills and test negative for pregnancy, contact your doctor.

About the Author

Michelle Powell-Smith has been writing on a variety of subjects from finance to crafts since 2004. Her work appears on various websites. She holds a bachelor's degree and a master's degree in art history from the University of Missouri-Columbia, which has provided strong research skills and a varied range of interests.

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