If you’re a young woman who might be pregnant, you may wonder how do home pregnancy tests work. What do you do if the test is positive? Can they fail?
Home pregnancy tests are a very common first step for many young women who suspect they might be expecting. Home pregnancy tests detect a hormone HCG (human chorionic gonadotropin) that increases in early pregnancy. It is often referred to as the “pregnancy hormone.” Let’s look at HCG, how pregnancy tests work, reasons a home pregnancy test might be inaccurate, and help you determine your next step.
What Is the Hormone HCG?
Around 7-10 days after fertilization, your body begins to develop tissue that will transport nutrients and oxygen for the pregnancy. During this development, your body will produce the hormone HCG.
HCG signals your body to perform various functions related to pregnancy such as stopping menstruation, thickening the uterine lining to support the pregnancy, and producing other hormones.
Your HCG levels rise very fast early in pregnancy and can be detected as early as 8 days after fertilization. The amount doubles about every three days.
How Do I Take a Home Pregnancy Test?
Home pregnancy tests can be obtained from medical suppliers such as a local pharmacy. With a urine test, you will collect urine on a strip of reactive paper attached to the indicator stick. If it detects HCG higher than a certain level, the device will show a positive pregnancy. This is usually shown within a few minutes on the stick by a plus sign, two lines, or even the word “yes.”
HCG levels can also be detected in blood tests, but these are primarily done in a clinic setting.
When Should I Take a Home Pregnancy Test?
A pregnancy test will be more reliable if you wait for a missed period. Since HCG levels take about a week or more to start rising, taking a pregnancy test too soon after sex may show an inaccurate result.
It can also help to take a pregnancy test first thing in the morning because there will be higher concentrations of HCG in your urine.
Can a Home Pregnancy Test be Wrong?
It is possible a home pregnancy test can be wrong. Most home pregnancy tests advertise that they are accurate at least 98% of the time. That means up to 1 in 50 tests will be inaccurate even when the test is used correctly. A Washington University study says up to 5% or 1 in 20 tests can be inaccurate. Several other factors can result in inaccuracy such as:
- User Error: An inaccurate reading can result from not following instructions, such as testing too early, using diluted urine from drinking too much before taking the test, or misreading the lines.
- Expired Tests: An outdated kit can lead to unreliable strips. Always check the expiration date before use.
- Abortion, Miscarriage, or Birth: If you take the test too soon after a recent pregnancy—whether it resulted in abortion, miscarriage, or delivery—this can also produce a false result because your body may still have elevated levels of HCG from the prior pregnancy for 6 weeks or more.
- Medications and Medical Conditions: Some fertility drugs “use HCG to help stimulate ovulation.” This could cause a false result on a home pregnancy test. It is also possible that HCG could be elevated for reasons unrelated to pregnancy, such as having a urinary tract infection.
Will a Home Pregnancy Test Show a Positive Result for an Ectopic Pregnancy?
Yes, even if your pregnancy is ectopic (implanted outside the uterus), a home pregnancy test should show a positive pregnancy because your HCG levels should still go up in early pregnancy.
The home pregnancy test you take will not reveal if the pregnancy is ectopic. This is why it is crucial to obtain an ultrasound to determine the location of your pregnancy. If your pregnancy is suspected to be ectopic, you would be advised to seek immediate medical attention.
What Should I Do If I Get a Positive Pregnancy Test Result?
A positive test is a big moment—take a breath and confirm your pregnancy from a medical professional. At Waterleaf Women’s Center, our licensed medical professionals can provide you with a pregnancy test and ultrasound at no cost and no insurance is required.
The ultrasound is very important because it reveals information about the age, location, and viability of your pregnancy. This information will equip you to make informed decisions about your next step.
You deserve compassion and professional medical service for your health and safety. Call or text Waterleaf confidentially today at 630-360-2256. We are here for you!
