But it's understandable if you're a little fuzzy on the details of what these devices actually look for to identify a pregnancy. At-home pregnancy tests check for the hormone hCG. HCG is short for human chorionic gonadotropin, which the body creates during pregnancy. Right after a fertilized egg attaches to the uterine lining, the placenta then forms and starts producing hCG 1.
A blood test can detect hCG about nine days after conception, and a urine test can detect it 12 to 14 days after conception, according to the Cleveland Clinic , although it varies—some especially sensitive urine tests can detect a pregnancy even earlier.
Then it remains consistent and starts to go down after delivery. Back to top. An at-home pregnancy test is designed to find hCG in pee 2. If the hormone is present, it triggers a chemical reaction and the test signals that you're pregnant. If hCG is not present, the test will say you aren't pregnant.
Some tests use plus and minus signs. Some digital pregnancy tests have a screen that plainly reads "pregnant" or "not pregnant. Seems simple, right? As Ina Garten would say, "How easy is that? Ultrasounds typically can't detect a pregnancy until a little later in your pregnancy and that's why at-home tests are so useful.
If you take a standard pregnancy test with line indicators, it's important to check the results according to the specific instruction of the test. If you let it sit too long before reading the results, urine on the test can evaporate and make it look like you have two lines instead of just one.
That might cause the test to look like it has a faint second line—making it positive—but it really only has one. The best way to avoid this: Read the pregnancy test's directions and follow them exactly. The popular pregnancy test brand First Response, for example, instructs users to wait three minutes after taking the test, then read it as soon as possible 4. The second most common reason Dr. Abdur-Rahman's patients get false positives is because the test is expired, he says. Abdur-Rahman says.
If you take a pregnancy test too soon after taking a fertility drug that contains hCG—like some injections that are often part of in vitro fertilization—you could get a false positive. Most miscarriages occur in the first 13 weeks of pregnancy 5. After you give birth or miscarry, hCG can persist in your body for months, Dr.
An ectopic pregnancy, menopause or problems with your ovaries also might contribute to misleading test results. It's possible to get a negative result from a home pregnancy test when you're actually pregnant. This is known as a false-negative.
You might get a false-negative if you:. There is a problem with information submitted for this request. Sign up for free, and stay up-to-date on research advancements, health tips and current health topics, like COVID, plus expert advice on managing your health.
Error Email field is required. Error Include a valid email address. To provide you with the most relevant and helpful information and to understand which information is beneficial, we may combine your e-mail and website usage information with other information we have about you.
If we combine this information with your PHI, we will treat all of that information as PHI, and will only use or disclose that information as set forth in our notice of privacy practices. You may opt-out of e-mail communications at any time by clicking on the Unsubscribe link in the e-mail. Our Housecall e-newsletter will keep you up-to-date on the latest health information. Mayo Clinic does not endorse companies or products.
Advertising revenue supports our not-for-profit mission. Any use of this site constitutes your agreement to the Terms and Conditions and Privacy Policy linked below. A single copy of these materials may be reprinted for noncommercial personal use only. This site complies with the HONcode standard for trustworthy health information: verify here.
This content does not have an English version. This content does not have an Arabic version. See more conditions. Healthy Lifestyle Getting pregnant. Products and services. Home pregnancy tests: Can you trust the results? Could you be pregnant? Get answers to common questions about home pregnancy tests. The embryo will still produce hCG, even though it has implanted in the wrong place.
That can cause a false-positive reading on an at-home pregnancy test. Ectopic pregnancies are medical emergencies. Ectopic pregnancies can be damaging to the woman if left untreated. Extreme blood loss or loss of the reproductive organs can occur. You may continue to test positive for pregnancy following the loss of a pregnancy, either through miscarriage or abortion.
During pregnancy, hCG levels continue to rise as the placenta grows, doubling every few days and peaking at around 10 weeks. The hormone can remain in your blood and urine for up to six weeks following the end of the pregnancy.
This will cause hCG levels to remain elevated. When this occurs, a minor surgical procedure called a dilation and curettage D and C is often required to remove the tissue. Check the expiration date before using the test. Even with these safeguards, user error can occur. One of the most common mistakes is taking the test too early during your cycle.
This can cause either a false negative or a false positive. Use the test when your urine is very concentrated, like when you first wake up in the morning. Leaving the dipstick in your urine stream for the exact amount of time allotted is also important. Consider setting a timer on a stopwatch or your phone. That can help you track how long the dipstick has been in your urine stream.
Checking your results during the result time frame is also important. Sometimes an evaporation line can be mistaken for a positive pregnancy test. The lines are usually a bright color, such as pink, red, or blue.
Sometimes, a faint-colored second line will appear. This line may represent an early pregnancy or it may be an evaporation line. Evaporation lines may show up on a test you view after your urine has evaporated completely. One of these is the synthetic hCG trigger shot, sold under the following brand names:. The hCG shot helps follicles release mature eggs.
It may cause a false-positive reading on an at-home pregnancy test, particularly if the test is taken too early. Other medications can also cause false-positive pregnancy tests. Rarely, certain medical conditions can cause a home pregnancy test to give a false positive.
0コメント