Teen Pregnancy Help: Pregnancy Tests – How do they work? How Accurate Are They?

It’s important to remember that if you think that you are experiencing an unplanned teen pregnancy, help is available to you. We understand that this can be an intensely emotional situation, especially if you’re just a teenager. You may find yourself feeling anxious, scared, and/or unsure of what comes next. There are so many thoughts that run through your mind – am I ready for this? When do I tell my parents? Is this test even accurate? 

While we can’t answer all of those questions for you right now, we can help you better understand how pregnancy tests work, when you should take one and their overall accuracy. 


Teen Pregnancy Help: How Do Pregnancy Tests Work? 

We don’t want to get too technical here, but basically, pregnancy tests work by looking for and measuring the amount of human chorionic gonadotropin (hCG) in your body. 

With at-home pregnancy tests, hCG is detected through urine via a strip of reactive paper. Each test is different, but generally, they’ll show a plus sign or double vertical lines to indicate a positive result. Some may even just say, “pregnant.” Since all tests are different, it’s critical that you read the instructions that come with the test to fully understand how to administer it, how long it takes to get a result, and what indicates a positive or negative result. Many tests also have a control window, so make sure you know what each window on the testing device represents. 

Beyond at-home testing, you can also have a pregnancy test done via blood sample by a medical professional. Like any other blood test, the medical professional will draw a small amount of blood and send it to a lab for testing. Once again, the lab will look to see how much hCG is detected in your body to determine whether or not you are pregnant. 

Teen Pregnancy Help: How Accurate Are Pregnancy Tests? 

At-home pregnancy tests are extremely accurate, and blood tests done by medical professionals are even more accurate. Pregnancy test manufacturers generally state that at-home pregnancy tests are between 97-99% accurate when administered properly. However, it’s important to note that false-negative results are rather common, especially early in pregnancy. This is because it takes several weeks for your body to build up enough hCG to be detected by the at-home test – which we’ll dive into later. 

The vast majority of medications have no effect on the test results with the exception of fertility drugs. The reason fertility drugs affect pregnancy tests is that these medications often contain hCG itself, the hormone which the pregnancy test is actively trying to detect. Other medications that may affect the accuracy of a pregnancy test are barbiturates, antihistamines (including promethazine), diuretics, methadone, and anti-anxiety medications like Valium or Xanax. However, this is much less common and typically should not affect tests taken several weeks into pregnancy. 

Three Ways To Better Ensure an Accurate Pregnancy Test Result

  • Do the pregnancy test as early in the morning as possible. This is when hCG levels in urine are most concentrated and easily detected. 
  • Make sure you haven’t gone to the bathroom for several hours (at least four hours) before taking the test. This also helps ensure a higher concentration of hCG in the urine. 
  • Avoid drinking an excessive amount of fluids prior to taking a pregnancy test. While this will increase the volume of urine in your bladder, and make it easier to go to the bathroom, it can also dilute the hCG present in your urine, resulting in a false-negative test result.  

Teen Pregnancy Help: When Should I Take a Pregnancy Test? 

The hormone hCG, which pregnancy tests aim to detect, can be found in either blood or urine, but your body does need some time to accumulate hCG.  The first few days following conception (the moment you first get pregnant), your body will begin to produce hCG. With each subsequent day, the body produces more and more, and after 1-2 weeks, there should be enough hCG in the body to prompt an accurate test result. If taken earlier, there might not be enough hCG in the body to be properly detected via urine test. 


It’s important to remember that if you’re experiencing an unplanned teen pregnancy, help is available to you. You have options, and the choice of how to move forward is 100% yours to make. If you’d like to learn more about your teen pregnancy options in Florida, or find yourself wondering how to “put my baby up for adoption,”  The Law Offices of Berkowitz & White PLLC would be happy to speak with you. Everything we discuss is confidential and non-binding. 

Call us Toll-free at (877) 777-5070

Text us at (561) 841-3065 or (850) 610-4166

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