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Pregnancy test information

Whether you're trying to conceive or have just noticed some weird changes that you’re thinking could be early signs of pregnancy, there’s only one way to find out for sure – buy a pregnancy test and find somewhere private to POAS (pee on a stick). Here's everything you need to know about when to take your test, as well as how they work and which one to go for.

By Mumsnet HQ | Last updated Mar 20, 2023

Woman taking a pregnancy test

When to take a pregnancy test

If your period's late and you're asking yourself “am I pregnant?”, you might not have to wait as long as you think to find out – you can take a test fairly early on. Most of them can be done from the day your period is due. If your cycles aren't regular or you don't know when ovulation happened, take a test 21 days after you last had unprotected sex.

How early can I take a pregnancy test?

Some newer types of test are so sensitive they can be taken as early as eight days after conception, but be aware that if you get a negative result you won't know for sure that you're not pregnant until after a missed period, so it's worth waiting as long as you can.

Some tests are designed to detect early pregnancy, so if you just can't wait to pee on that stick, you're best off going for one of these. An early detection test is more sensitive to the hCG hormone (or 'pregnancy' hormone), giving you a better idea of whether you might be expecting, earlier. There are a few reasons you might be eager to do this as early as possible – to avoid drinking alcohol, for example (who really wants to turn down a couple of champagnes at a wedding if they're not actually pregnant) or so that you know to make changes to your diet if you haven't already…or simply because you Just. Need. To. Know.

Keep in mind, though, that a negative result isn't 100% a negative, so probably best not to go overboard with the champers either way (sorry).

When is the best time of day to take a pregnancy test?

It is best to take your test in the morning when levels of the pregnancy hormone hCG in your urine will be at their highest. You will get an accurate result sooner than with urine samples taken in the afternoon or evening. If you've been for a wee during the night, the concentration level won't be as high in the morning, though, so you'd be best to try again the next morning.

How accurate are they?

Many home pregnancy tests claim to be 99% accurate, as long as you follow the instructions correctly. Follow them to the letter for the best chance of getting an accurate result, which means no chucking the instruction leaflet away and going off-piste à la Ikea.

Can a pregnancy test be wrong?

In a word, yes. If you get a positive pregnancy test result, the chances are that you are indeed pregnant. If you get a negative result, however, it is less reliable. Some research suggests that home tests are not accurate enough to detect a positive result in the days immediately after a missed period. So, if you think you might be pregnant but get a negative result on the day of your missed period or in the days following, try doing a test again in a couple of days.

Early signs of pregnancy

Which is the best test?

You don't need to go to the GP for a test but, unfortunately, you do need to do something a bit more scientific than an online one or a pregnancy quiz. Over-the-counter tests are pretty accurate these days, but they do differ slightly in terms of how they work, how they display results and how sensitive they are – and therefore how soon you can use them. Here's the lowdown on some of the most popular tests:

Clearblue digital pregnancy test

Clearblue claims 99% accuracy across all its products and offers a range of different tests to choose from, depending on what you're after. If you like a bit of 'data', the Clearblue Digital With Weeks Indicator tells you in words if you are “pregnant” or “not pregnant” as well as how many weeks you are. It can be done up to five days before your period is due.

The Clearblue Early Detection test can be done up to six days before a missed period if you're feeling impatient. And, if you're the sort who likes your result with a bit of a drumroll, you could try Clearblue's Digital Test With Countdown for a Nasa-style 10 to zero to your result in words.

The company also does two tests with a colour-change tip so you can be sure you've hit the spot, as well as a 'rapid results' test for the super impatient.

First Response pregnancy test

The First Response Early Results test allows you to test up to six days before your missed period. Like the Clearblue products, it promises 99% accuracy from the expected day of your period. There's also a First Response Rapid Results test that will tell you whether you're expecting in less than a minute. (That's the results you'll get in less than a minute, not the baby, to be clear. No test is that clever.)

Asda pregnancy test

Asda's own home test can be done up to four days before your period is due and also promises 99% accuracy on the day of your period – accuracy will be lower before. It doesn't have any fancy bells and whistles but retails at a much more wallet-friendly price, so if you're the sort to want to do 20 tests, just to be Absolutely Sure, you can indulge that need.

Boots pregnancy test

Boots do a digital test that tells you clearly (using words) if you are pregnant or not. It delivers results in three minutes and is 99% accurate on the day your period is due. It can also be done up to four days in advance but is less sensitive than the more expensive branded products so, when done early, is slightly less likely to give a positive result even if you are pregnant.

However, there is also a Boots Five Days Early test which, as the name suggests, can be used five days early for more accurate results. This one's results are displayed using two lines for pregnant and one line for not pregnant.

Tesco pregnancy test

There's a no-nonsense, at-least-99%-accurate Tesco test that gives you a result in one minute. There's also a (more expensive) digital version that uses words to give the result, for those who don't like squinting at pink lines.

Superdrug pregnancy test

Superdrug has a whole range of tests, starting at jaw-droppingly bargainous prices, that are still over 99% accurate, and great for if you want to check, check, and check again. If you're looking for something with more bells and whistles, there's a slightly costlier version that detects pregnancy earlier.

Clear & Simple Digital Pregnancy Tests recalled

The manufacturers of Clear & Simple Digital Pregnancy Tests are asking customers to check their lot number after some tests have returned inaccurate results. Guangzhou Wondfo Biotech is recalling one lot of faulty pregnancy tests after they produced a small number of false positive results.

While only one lot is affected, the manufacturer estimates this amounts to more than 58,000 tests in the UK. If you've purchased an affected test, you should use an alternative testing method and return any affected Clear & Simple tests to their pharmacy or shop. The affected lot number, which can be found on the end of the box and is printed on the sachet, is DM10220170710E, and the expiry date is January 2020.

Dr Duncan McPherson, MHRA’s Clinical Director of Medical Devices, said:

“It is important people check the lot number of any Clear & Simple Digital Pregnancy Tests they have purchased to see if they have a product from an affected lot.

“If you have any questions about using digital pregnancy tests, please speak to your healthcare professional.

“Patient safety is our highest priority. We strongly encourage anyone to report any issues with this product, or more generally with any medical device, to our Yellow Card Scheme.”

How do you take a pregnancy test?

Most over-the-counter tests contain one or two sticks. You pee on the stick, and the result (positive or negative) appears after several minutes. Read the instructions carefully, because different manufacturers' tests vary slightly, but it usually involves reading one or more lines. If you're feeling particularly flustered, you can always go for the fancypants digital type that says “pregnant” or “not pregnant”, so there's no chance of you misinterpreting the lines.

It used to be that you had to test the urine from your first wee of the day, but now you can use urine collected at any time. If you're doing an early test, however, don't drink tonnes of water beforehand as you don't want your urine to be too diluted.

If you think you might have trouble weeing directly on the stick (and let's face it, we don't all have perfect aim), you can always wee into a clean cup and dip the stick into it for a few seconds.

Things not to say to pregnant women

Where can I get a test?

Your GP can test to see if you're pregnant, but over-the-counter tests are just as accurate and most surgeries accept these as confirmation that you're on stork watch. You can also get a free test from your community sexual health clinic (aka family planning clinics or GUM clinics), NHS walk-in centres and Brook Advisory Centres (if you're under 25).

Alternatively, get yourself off to a high street chemist or the supermarket, buy your test of choice and prepare to join the legions of women who've discovered the profound news that they're going to have a baby while perched on the loo or the side of the bath.

My GP says a line is a line, regardless of the cost of the test – they show the presence of the same hormone. The more expensive tests may just be more sensitive.

How do they work?

In a nutshell, they work by detecting the presence of the pregnancy hormone human chorionic gonadotrophin (no wonder they call it hCG) in your urine. The level of hCG goes up steeply during the early weeks of pregnancy. However, some women have low levels of hCG at the time their period would occur so it is possible to get a negative result and still be pregnant.

Different tests have different levels of sensitivity but the packaging will tell you how sensitive yours is. It's usually described in terms of mIU/ml (milli-international unit per millilitre, or thousands of international units per millimetre). They generally range in sensitivity from 20mIU/ml to 40mlU/ml. The lower the number, the more sensitive the test is and, therefore, the earlier it can tell you whether you are pregnant.

Negative test results

Getting a negative result can be really disheartening and the stress of trying to conceive can take its toll. If you've been trying for a while and feel you might be having problems getting pregnant it might be worth speaking to your GP about it.

If you get a negative result but you have lots of pregnancy symptoms, such as a missed period or morning sickness and still think you could be pregnant, then wait a couple of days and do another test. NHS Choices recommends speaking to your GP if you get a negative result after the second test but your period still hasn't started.

Positive test results

If you get a BFP (big fat positive, in Mumsnet-speak), congratulations! Time to crack open the erm, orange juice and get busy with the baby names book! Or you could take the more sensible route and make an appointment to see your GP so that you get your antenatal care started, and start familiarising yourself with the dos and don'ts of pregnancy so you can give your baby the healthiest start possible.

If you've got a positive test, I personally wouldn't take any more, otherwise you're just chucking money away to see what you already know in my humble opinion!

Faint line on a pregnancy test

Seeing a really faint line appear can be so disappointing – especially when you were expecting a bold stripe announcing, beyond a shadow of a doubt, that you're pregnant. It's also pretty confusing. Does it count? Does it not? Do you really need to be inspecting it with the magnifying glass you found in the kitchen junk drawer?

If your test shows an extremely faint positive line, first thing's first – check you followed the instructions. If you didn't, take another test. But if you read that leaflet cover to cover and know you got it all right, then there's good news – it's likely to be a positive result. If you're only a few days pregnant, there won't be much hCG to detect (hence the faint result), but a faint line still means that the test picked up traces of it. Wait a few days and then try again for a more clear-cut indication.

Very rarely, a faint line can mean a false positive result, unfortunately. Things such as medication or hormonal fertility treatment can affect the outcome, however, the chances are very much in your favour if neither of those is applicable to you.

How pregnant am I?

The fancier types of test sometimes will say on them that you are “one to two weeks” or “two to three weeks” pregnant if you get a positive result. Don't forget you need to add two weeks to this as this represents ‘time since conception’. Midwives (and everyone else) count pregnancy from the first day of your last period, so if you conceived four weeks ago you are six weeks pregnant, and so on.

If you're still confused, try a pregnancy due date calculator to help give you a clearer idea.

pregnant woman holding a clock
Weird Pregnancy Symptoms

Can you get a false positive test result?

It is possible to get a false positive result. This is where the test shows a positive result but you not actually pregnant. Causes of a false positive result include chemical pregnancy, ectopic pregnancy, recent miscarriage, recent abortion and certain medications.

If you haven't come off the pill it makes no odds to the test. Hormone-based contraceptives (the pill, implants and injections) don't affect the results, so a positive result means you're pregnant, whether or not you're on the pill.

Remember that a negative result is much more often incorrect than a positive one, though, so if you still think you're pregnant wait a couple of days and repeat the test. If you have an unplanned pregnancy and aren't sure you want to be pregnant you can find lots of women who've been in a similar position on Mumsnet's pregnancy choices Talk board.

My test is positive but I'm bleeding. What does this mean?

It's very common to experience bleeding in early pregnancy. It can be a sign that something's amiss, so you do need to see your GP or midwife to check as miscarriage is sadly quite common in the early weeks of pregnancy. However, bleeding and spotting is also common at this time and many women who experience bleeding during early pregnancy go on to have full-term pregnancies, so don't instantly assume the worst.

"I had a positive four days before my period was due with First Response early response. Was extremely faint though!"

"I had negatives all the way up to the day my period was due and then I got a faint line on the day of (so 14 days post ovulation). A line's a line though, as I'm 27 weeks now."

"Negative on Sunday, positive on Thursday morning – the day my period was due!"

"The best time is to test after you're due but I know how hard it is to wait"

"Wait until your period is due and make sure you use the first wee of the day. Yes, it's true that some women can get a positive result as early as four or five days before their expected period (depending on brand) but not everyone will detect this early."