All pregnancy test results are based on whether or not the pregnancy test itself was able to detect a very specific pregnancy related hormone called human chorionic gonadotropin, or hCG. This hormone is present in the blood and urine of all pregnant women and is the first step in acknowledging pregnancy.
Different Types of Pregnancy Tests
Pregnancy is revealed through either a blood test or a urine test. In most cases a woman will conduct her own urine test and then after receiving a positive result will have a blood test ordered by her doctor for further confirmation. However, not all urine tests are alike. There are some that have an increased sensitivity to hCG and can detect as little as 20 mIU of hCG within seven to ten days past ovulation. Others are designed to only test after the first day of a woman’s missed period when her hCG level should be at least 40 mIU.
For the most part, blood tests are superior to urine tests as there is less room for error; and they can determine pregnancy six to eight days after ovulation. There are two different types of blood tests and they are only conducted at a clinic or doctor’s office. The first is the quantitative blood test which calculates the exact amount of hCG that is in the blood. The second is a qualitative hCG blood test which simply provides a positive or a negative answer to whether a woman is pregnant.
Medications and Pregnancy Test Results
Regardless of which pregnancy test a woman takes, most over-the-counter medications and drugs will not affect the test result. The Office on Women’s Health is part of the U.S. Department of Health and Human Services. Their mission is improving the health of all U.S. women and girls. According to their Pregnancy Tests Fact Sheet most over-the-counter and prescription medication will not affect the results of a home pregnancy test. This includes antibiotics and birth control pills. The only medications that can display a false positive test result are those that contain the pregnancy hormone hCG, such as most medications used to treat infertility.
Medications that contain hCG, or are used in combination with hCG, include, but are not limited to, Humegon, Pregnyl, Profasi, Pergonal, and Novarel. These may give false positive results if the pregnancy test is performed within 7-14 days of the last drug administration.
Antibiotics, analgesics or pain killers, birth control pills, and hormone therapies that contain Clomid or Serophen (clomiphene citrate) should not affect the test result.
Furthermore, narcotic drugs like ecstasy, cocaine, marijuana, heroin and even alcohol will also not affect a pregnancy test result. A woman should also not be under the influence of narcotics when performing a pregnancy test and it is highly advised that women refrain from using drugs and alcohol when trying to become pregnant.
Home urine pregnancy tests are approximately 97% accurate when they are performed properly. As they are fairly inexpensive when compared to a blood test, are simple to use, provide a fast answer, and can be easily obtained online or over the counter, they are a great choice for predicting pregnancy.