Medically reviewed by Cordelia Nwankwo, MD
If you’ve recently had unprotected sex, you often wonder when to test for pregnancy. The short answer: home pregnancy tests are most accurate when taken late after your period. In general, you can take an early detection pregnancy test eight days after conception. However, experts suggest that you get your most accurate test results if you test 10 to 14 days after having unprotected sex.
Pregnancy tests work by detecting the presence of human chorionic gonadotropin (hCG) – a hormone that people with female reproductive systems produce after conception and implantation. It can take up to two weeks after unprotected sex for your body to produce enough hCG for the test to properly detect the hormone.
Keep in mind that taking a pregnancy test too soon can cause a false negative. Here’s everything you need to know about when to test for pregnancy and how to avoid getting an inaccurate test result.
If you want to avoid pregnancy after unprotected sex, consider emergency contraception. Different choices include over-the-counter or prescription pills and intrauterine devices (IUDs).
Why you should take a pregnancy test
You may consider taking a pregnancy test if you have any reason to believe you may be pregnant. These reasons can be:
When should you take a pregnancy test?
You will get the most reliable and accurate results if you wait to test for pregnancy if your period is late. If you don’t want to wait that long (or if you don’t have regular periods), wait at least 10-14 days after having unprotected sex to take the test.
To maximize the accuracy of a pregnancy test, it is best to take the test first thing in the morning. In general, if you use a home pregnancy test, you will probably urinate on a stick to get your results. That said, it’s best to use your first urine of the day for the pregnancy test.
Human chorionic gonadotropin (hCG) levels are most detectable when the urine is concentrated (not diluted). Your urine concentration is highest after a period when you haven’t had much to drink or used the bathroom, which usually happens while you’re sleeping through the night.
What can affect the test results?
Home pregnancy tests can be up to 97% accurate if you use them correctly. Read and follow all directions that come with your test to get the most reliable results.
But sometimes it is possible to get a false negative or positive. The most common reasons for inaccurate results are:
diluted urine: Drinking too much water or other liquids before taking the test can dilute the urine and result in a false negative.
Blood in the urine: Blood in the urine can cause a false positive result.
Testing too early: Testing before the body produces enough hCG can result in a false negative.
Improper test usage: Improper use of the test may mean that the pregnancy test instructions are not followed correctly, that an expired or damaged test is used, or that the result window is checked too early or too late.
Medications or blood transfusions: Although not common, some medications can cause a false positive. This is not an exhaustive list, but medications that can affect your test results include fertility drugs, certain antidepressants, and blood transfusions.
Chemical Pregnancy: A chemical pregnancy occurs when a fertilized egg fails to implant in the uterus. This can result in a positive pregnancy test followed by a miscarriage. Testing too early increases the risk of a false positive result from a chemical pregnancy.
Medical Conditions: Medical conditions, such as ovarian cysts, adenomyosis, or certain types of cancer, can increase hCG levels in the body and lead to a false positive result.
Symptoms of early pregnancy
Early pregnancy symptoms can start as early as a week after conception. However, some people have no symptoms for several weeks. If you are experiencing early pregnancy symptoms, you may notice the following changes in your health:
Not all pregnant people experience symptoms, especially during the early stages of pregnancy. Symptoms also vary from person to person. Additional symptoms you may have in the first trimester of your pregnancy include:
Light spotting or cramping
Food aversion or cravings
However, it is important to note that pregnancy symptoms can sometimes mimic symptoms of other health conditions and lifestyle changes. Factors that can trigger pregnancy symptoms and cause changes in your health include:
Stress, depression or anxiety
Hormonal changes or imbalances
Lack of sleep
Excessive weight changes
Food poisoning or stomach ailments
A quick overview
If you think you might be pregnant or have recently had unprotected sex, it’s natural to want to get tested for pregnancy to find out more about your status. You will get the most reliable test results after you miss your period. Your body doesn’t produce enough hCG (the hormone pregnancy tests detect) until 10-14 days after conception. If you don’t want to wait until you miss your period, experts recommend waiting about two weeks after having unprotected sex to test for pregnancy.
To ensure the most accurate pregnancy test results, it is also important to:
Check the expiration date of the pregnancy test
Follow the pregnancy test directions carefully (including how to take the sample and how long to wait for results)
Avoid drinking large amounts of liquid before taking the test (take it first thing in the morning if possible)
Consult a health care professional if you are concerned that a drug or illness is causing a false positive
If you think you are pregnant and get a negative result, consider retesting after you miss a period or after two weeks of unprotected sex.
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Read the original article on Health.