Pregnancy tests: What you need to know
When is the best time to test, where can you buy testing kits and are they 100% accurate? All is revealed here in our quick guide to pregnancy tests.
At a glance
- It usually takes two weeks after you get pregnant to get a positive result with a pregnancy test
- Make sure you read the instructions as brands differ in how they tell if you are pregnant or not
- Don't peek too early at the test as it will take a few minutes before the answer is shown
How do pregnancy tests work?
Pregnancy tests work by detecting the hormone hCG (human chorionic gonadotrophin) in your urine. This is the hormone that is produced by the cells that will form into the placenta so will give you an accurate answer to whether you’re pregnant or not. When you become pregnant the amount of hCG in your body will increase rapidly. It usually takes two weeks after you get pregnant to be at a level to show up as a positive pregnancy test, so try not to test too early!
Which pregnancy test is right for me?
When shopping for pregnancy tests you'll see there are several factors to think about before choosing one.
The key factors to look for are:
- Earliest ability to detect pregnancy after conception
- When you can take the test
The more sensitive the test is to the pregnancy hormone, hCG, the quicker it will be able to accurately test for pregnancy. Check the box for how early the test you are thinking of buying can test as some will be able to test earlier than others.
Pregnancy tests can vary from a few pounds to more than a tenner but although they will all give you same result, there are some differences in what you get. The cheaper tests are more likely to have a classic 'line' on the screen that you need to look for to see if you are pregnant, and no line indicates a negative result. If you invest more in your chosen test, it will clearly state whether you're 'pregnant' or 'not pregnant'. So the answer is the same in both but more explicit with the fancier test. You can however invest more in a test that can indicate roughly how far along you are straight away, but if you feel the cost of this is too much, don't forget your GP will verify this for you anyway.
When to take the test
If you are running out to get a test and desperate to take it before the next morning (most tests advice you take the test during your morning wee), make sure you choose one that specifically says you can test any time of the day but try to remember hCG is most concentrated your morning urine.
How early can I use a pregnancy test?
hCG starts being produced around six days after fertilisation, and it takes about two weeks from conception for hCG to reach a level that will be picked up to give you a positive pregnancy test. This is probably around the time your period is due, so a great time to do that test! Pregnancy testing at home is not 100% accurate though, and if you do get a negative result, it’s sometimes worth doing another test a few days or week after your missed period to see if it comes back positive as the hCG levels increase.
How do I use a pregnancy test?
Start by reading the instructions carefully, as brands differ. Make sure, you know how the test will tell you if you’re pregnant or not. Also it’s a good idea to check the expiration date on the test if you’ve not recently bought it to ensure it’s in date and as accurate as possible!
To perform the test you need to get urine on the end of the stick. You can wee into a urine pot and pop the stick in it, or you can wee over the stick, into the loo. Then there will be a loooooong wait of a few minutes before the answer is shown. Best not to peek, as you may mistake the reading if you look while it’s working.
Different brands of test will vary in how they tell you the result. Some will show a pink or blue line for a positive pregnancy test or a plus symbol. It’s also now possible to get pregnancy tests with a digital readout that will tell you if you’re pregnant, these usually come with an old fashioned lines result too so you can confirm that the readout is correct.
Any special instructions?
The best time to take one is first thing in the morning, as the hormone will be more concentrated in your urine - though you can take one any time of the day. Try not to drink much fluid before a test, as it can dilute the hCG in your urine.
Where can I get a pregnancy test?
You can get pregnancy tests free of charge from your GP, local community sexual health clinic and NHS walk-in centres. You can also buy do-it-yourself pregnancy testing kits from most chemists and large supermarkets.
Does my GP test me too?
Not usually, as home kits are just as good as the ones doctors use. If they think it’s necessary for some reason, a doctor may give you a urine or blood test to confirm the pregnancy.
Are home pregnancy tests accurate?
Home test kits have become extremely reliable over the past couple of decades, so if you get a positive result, then you almost certainly are pregnant.
If you've recently had a miscarriage though, be cautious, as the levels of hCG hormone in your blood take a while to return to normal. It’s also possible to have a false positive if you’ve been taking any fertility drugs containing the hCG hormone and if you’re using an expired or faulty pregnancy test.
Negative results, however, are less reliable. For example, if you test really early on, before the hormone has risen to a level that can be tested it will say negative even if you’re pregnant. So even if you’re desperate to find out, dig deep, be patient and try again a few days after your period would have been due.