Home pregnancy tests are very accurate if you follow the instructions correctly. They are as accurate as the tests used by health professionals. However, if you don't follow the instructions properly, or take the test too early, the result may not be reliable.
When you first become pregnant, your body produces large quantities of the pregnancy hormone called human chorionic gonadotrophin (HCG). This hormone plays a key part in your pregnancy's early development, as well as stopping your periods. HCG is present in your blood and your urine. Home pregnancy tests detect HCG in your urine.
You can buy home pregnancy testing kits over-the-counter (OTC) at most pharmacies and at many large supermarkets.
Carrying out a test
You can test a sample of your urine from the first day that your period would normally be due, which is usually about two weeks after you conceive. You can do the test at any time of the day, although your urine is more concentrated first thing in the morning. You should avoid drinking too much fluid before doing the test because it can dilute the level of HCG in your urine.
Make sure that you read the instructions carefully before you do the test because different testing kits use different methods, and display the results in different ways.
Positive test results
After taking a pregnancy test, if the test result is positive, you're almost certainly pregnant. False positive results - where the test says that you're pregnant when you're not - are extremely rare.
As soon as you find out that you're pregnant, it's a good idea to visit your GP. Due to the fact that home pregnancy tests are so accurate, your GP is unlikely to repeat the test.
As HCG is sometimes used in fertility treatment, it could cause a false positive result. You should wait 14 days after having fertility treatment before taking a pregnancy test.
Negative test results
If you have a pregnancy test and the result is negative, you may not be pregnant. However, negative test results are less reliable.
False negative results - where you're pregnant but the test says that you're not - are more common than false positive results. For example, if you do a pregnancy test too early, before the day that your period would normally be due, you may get a false negative result. This may be because the amount of HCG in your body has not built up to a high enough level yet.
Pregnancy tests vary in their sensitivity (how soon they can detect HCG and what level of the hormone needs to be present). You can find information on the box about how sensitive a pregnancy kit is.
If your test result is negative, and you think that you might be pregnant, you could wait a few days before trying another test, or go you could go straight to your GP.
If you think that you're pregnant after a second negative result, you should check with your GP. HCG can also be detected in your blood around 10 days after you conceive, and your GP may advise you to have a blood test.
Complications
If your periods are irregular, it can be difficult to work out when your period would normally be due. When you decide to do the test, try allowing for your longest cycle over the last few months.
Similarly, if you've recently stopped taking the contraceptive pill, your natural cycle may not have returned, so you may try testing too soon.
If you get a negative test result in situations like these, try the test again three days later. Many home pregnancy kits include two tests, which is convenient if you need to do a test more than once.
If your first pregnancy test result is positive, but a later one is negative, or your period then arrives, it's possible that you may have had an early miscarriage. Your period may be heavier than usual. If this happens, it doesn't mean that you can't conceive again. If you think that you may have had a miscarriage, you should visit your GP, or midwife, for advice.
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