The results from a pregnancy test are — to say the least — life-changing.
If you take a pregnancy test just a few days after unprotected sex and receive a negative result, you may think you’re in the clear.
Conversely, if you’re trying for a baby and test negative the week after unprotected sex, you may find you’re checking your ovulation tracker because you were sure you had the dates right.
Not so fast. Sometimes, pregnancy tests can give you a false negative result — which says you’re not pregnant even though you really are.
If you think that your pregnancy test mistakenly gave you a negative result because you tested too soon, keep reading this guide from PregnancyResource.org to discover how soon you should test again.
How Does a Pregnancy Test Work?
Before we discuss how long you should wait to take a pregnancy test, let’s go over how a pregnancy test works in the first place.
Essentially, an over-the-counter home pregnancy test checks your urine stream for human chorionic gonadotropin (hCG).
This is a hormone that pregnant women produce in high amounts to thicken the uterine lining and prepare it to carry a baby for nine months.
HCG begins to increase in urine about a week after conception — when a fertilized egg implants itself in the uterine lining.
Home pregnancy tests measure this increase by indicating high hCG levels in the urine, which is why test instructions either have you put the test stick directly into your urine stream or have you dip the test stick into a small cup of your urine.
A higher-than-normal amount of hCG will produce a color change in the testing strip, usually showing up as a second faint line or a plus sign on the display. If you’re not pregnant, there are generally no changes to the display at all.
False positive pregnancy tests have been known to occur in people who have experienced a recent pregnancy loss (miscarriage), are currently experiencing an ectopic pregnancy, or recently took a fertility drug containing hCG.
However, the vast majority of positive results are accurate — it’s the false negative results that can be misleading depending on when you take the test after unprotected sex.
How Soon Can You Take a Pregnancy Test?
If you’ve successfully conceived, you need to give your body time to build up the hormone hCG — otherwise, a pregnancy urine test won’t be able to detect it.
Even though early pregnancy tests exist, they are not always accurate since hCG levels are not always high enough to detect in the earliest stages of gestation.
The earliest possible time to consider taking a pregnancy test is about one week after conception. Of course, depending on your body, hCG levels may or may not be detectable by that point.
Home pregnancy tests are evaluated by the Food and Drug Administration (FDA) to be as accurate as possible.
That said, the tests are most accurate when you take them after the first day of your missed expected period.
If you have an irregular menstrual cycle, you can add 30 days to the last day of your most recent cycle and take a pregnancy test after that day.
If you’re taking an early detection pregnancy test, you can use it as soon as 10 days after conception for fairly accurate results.
Always follow the instructions on the pregnancy test kit for when exactly you should take it. When in doubt, make sure to consult your obstetrics-gynecology provider, i.e. your OBGYN.
What Happens If You Test Too Early?
However, for some women, this may not be enough time to build up detectable levels of hCG, resulting in a false negative test result.
Plus, there’s the issue of spending money on a pregnancy test just to have to buy another one.
Another problem with testing too early is that some women may think that they’re not pregnant, either resulting in a desperate search for other causes behind a missed period, or the potential to miss out on prenatal care, which is especially important in early pregnancy.
All in all, it’s better to wait until you miss your period before you take a pregnancy test.
Doing otherwise can lead to disappointment, time and effort put into the wrong resources, and even missing weeks or months of prenatal care.
How Long Should You Wait To Take a Pregnancy Test Again?
If you received negative pregnancy test results, you may feel disappointed and think you need to keep trying to get pregnant.
But if you’re actually pregnant, your body may tell you otherwise with early signs of pregnancy like morning sickness and breast tenderness.
The main reason you may have gotten a false negative is that you took the test too early. While some women may produce a lot of hCG early on, others may need more time for this hormone to build up in their urine.
You may have also gotten a false negative result for other reasons. For instance, drinking too much water right before testing can dilute hCG levels in your urine, which can make them undetectable by at-home pregnancy tests.
Likewise, if you didn’t follow the test instructions (such as exactly where to place the urine or how to orient the test stick while it processes results), you may also have a false negative.
If you waited until your first missed period and followed all the instructions on the test but still got a negative result, then it’s very likely that you’re not pregnant.
If you continue to experience classic symptoms of pregnancy, then you should see a healthcare provider for a blood test.
Blood tests are usually more sensitive than urine tests and tend to pick up on lower levels of hCG in the body.
After your second or third pregnancy test, it’s best to give it a rest. Schedule an appointment with a healthcare professional to rule out any unusual conditions and avoid taking another at-home pregnancy test.
Seeing yet another negative pregnancy test can be tough if you’re trying for a pregnancy. It’s best to stay as stress-free as possible — especially as you’re trying to conceive.
When taking an initial pregnancy test, it’s best to wait until after your first missed period.
If you get a negative test result that you think is false, you can take another test within a few days.
Just make sure to follow all of the instructions, and avoid drinking too much water the hour or two before testing.
If you get another negative result, make an appointment with your doctor for a blood test.
These tend to be more sensitive, meaning they might pick up on pregnancy when at-home tests weren’t able to.
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Bridget Reed is a Tampa-based content development manager, writer, and editor at GR0; specializing in content related to varying fields including medicine, health, and small businesses. Bridget went to St. Petersburg College and majored in Management and Organizational Leadership.
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