Unanswered questions are the worst. Especially when the question is whether you're pregnant or not. While it can be super tempting to bust out a box of home pregnancy tests the second you think you might be pregnant, you won't get a reliable answer if you test too early.
So, how long do you have to wait after unprotected sex to find out if you're pregnant? Read on to learn when you should take a pregnancy test, how the tests work, and what other signs of pregnancy you can look out for.
Quick answer: How soon can I take a pregnancy test?
For the most accurate results, it's best to take a pregnancy test 5 to 10 days after the first day of your missed period. According to manufacturers, most at-home tests are 99% effective, as long as you wait to take them until you're sure that your period is late.
If you take the test too soon, there's a chance it could give you a false negative (meaning that it says you're not pregnant when you actually are).
If you're not sure when your period was supposed to start, that's okay. Just wait at least two weeks after having unprotected sex to take your first test. That's typically the earliest that a home pregnancy test may be able to detect a pregnancy. If that test is negative, you should wait a week, then take another test to confirm your results.
What is a home pregnancy test?
Home pregnancy tests are made to detect a hormone called human chorionic gonadotropin, also referred to as the "pregnancy hormone." This hormone, hCG, is produced in small amounts by your pituitary gland, colon, and liver. But they don't make enough to be detected in a home pregnancy test.
Typically, hCG levels only get that high after a fertilized egg is implanted in the uterine lining (aka, when you get pregnant). After implantation, your body seriously ups its production of hCG. Around the time of your first missed period, the levels of hCG in your urine should be high enough to result in a positive pregnancy test.
Home pregnancy tests can be purchased at the drugstore or the supermarket. Prices vary, but you can usually find a pack of two or three tests for under $10. When you're browsing the shelves, just know that each brand of pregnancy test should work the same, regardless of price. In other words, the cheapest pregnancy tests work as well as the more expensive ones!
There are two main kinds of home pregnancy tests. One has you pee on the end of a test stick. The other has you urinate in a cup, then put the end of a test strip in the cup.
No matter which kind you choose, make sure you read the instructions before you take the test. They'll let you know the right way to use the test, how long you have to wait for results, and how to read the results when they show up.
Note: Don't forget to check the expiration date before you take a pregnancy test! Expired tests can lead to less accurate results.
Why do I have to wait to take a home pregnancy test?
You don't actually get pregnant immediately after having sex. (That's why you can take emergency contraception up to five days after having unprotected sex.) First, sperm has to reach and fertilize an egg. Then, that fertilized egg has to implant in the uterine lining. Then, you're officially pregnant.
It takes time for this to happen. Just how much time depends on two things---when you ovulate and when you have sex.
Ovulation is when your ovary releases a mature egg into your fallopian tube. That egg needs to be fertilized within 12 to 24 hours after ovulation for you to get pregnant. Sperm, on the other hand, can stay alive in the female reproductive tract for up to five days.
So, it's possible for an egg to be fertilized up to five days after you have sex. It's also possible for it to be fertilized on the day you have sex. It all depends on when you ovulate.
After the egg is fertilized, it still has to implant in your uterine lining. In most healthy pregnancies, the fertilized egg attaches to the uterine lining about 8 to 10 days after ovulation. But a test can't detect a pregnancy immediately after implantation. It takes some time (though not much) for your hCG levels to increase enough to show up on a pregnancy test.
Fun fact: HCG helps support a pregnancy by telling your ovaries to stop releasing eggs and start producing estrogen and progesterone full-time.
In the early days of pregnancy, the amount of hCG your body makes doubles every two to three days. By the time you reach your missed period, there should be enough hCG in your urine for a pregnancy test to give you a positive result.
To sum it all up, the level of hCG (the hormone that pregnancy tests look for) in your urine depends more on when you ovulated than when you had sex. That's why doctors recommend waiting until after your period is late to take a test.
When is the best time to take a home pregnancy test?
The best time to take a home pregnancy test is the first thing in the morning. That's when your urine is the most concentrated. Any water or other liquids you drink throughout the day may dilute your urine and make it look like you have less hCG than you really do. Testing in the afternoon or evening with diluted urine could lead to a false negative result.
What else can affect the accuracy of home pregnancy test results?
Besides testing too early and testing with diluted urine, there are only a handful of things that can cause a pregnancy test to be inaccurate. Testing too soon after taking fertility drugs that contain hCG could potentially give you a false positive. However, birth control, antibiotics, and most other medications shouldn't affect the accuracy of a home pregnancy test.
One situation that also leads to misleading results is an ectopic pregnancy, which is a potentially life-threatening situation in which a fertilized egg implants in the fallopian tube instead of the uterus.
What are the first signs of pregnancy?
When you need to take a pregnancy test, waiting around for your missed period can feel like an eternity. It's natural to look for other signs that could give you a clue about whether you're pregnant or not. A few symptoms (besides a missed period) that some women experience in early pregnancy include swollen or tender breasts, nausea, vomiting, fatigue, and an increase in how often you have to urinate.
Other symptoms include light spotting (way lighter than period bleeding), bloating, cramping, and changes in mood or food preferences. It's possible that some of these signs may start before your missed period and, therefore, before you'd test positive on a home pregnancy test.
However, pregnancy symptoms are different for everybody, and an hCG test is the most reliable way to know for sure if you're pregnant.
What should I do after I take a pregnancy test?
If your pregnancy test is positive, you can schedule an appointment with your doctor's office to confirm the results. They'll do a urine or blood test for hCG. If you're farther along (read: at least four or five weeks), they may also be able to confirm your pregnancy with an ultrasound.
During this first appointment, your doctor will also check your overall health and medical history. They'll talk with you about any diet or lifestyle changes that could increase your chances of a healthy pregnancy and give you an idea of what to expect in the coming weeks and months.
If your test is negative and you still don't get your period, you should test again in about a week and see if your results change. If you don't get your period after a second negative test, it may be time to talk to your doctor about other causes for your missed period, such as sickness, stress, or other medical conditions.
Whether you're hoping for a positive or negative result, waiting to take a pregnancy test isn't easy. If you're tempted to test early, that's okay. Just remember that any negative results will need to be confirmed by testing again after your missed period. If you don't want to spend money on extra tests, or you'd like to avoid the emotional rollercoaster of a false negative, it's best to test after your period is late.
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