How long after ovulation will a pregnancy test be positive

If you have missed a period and recently had unprotected sex, you may be pregnant. Pregnancy tests are most reliable from the first day of your missed period.

When you can do a pregnancy test

You can carry out most pregnancy tests from the first day of a missed period. If you don't know when your next period is due, do the test at least 21 days after you last had unprotected sex.

Some very sensitive pregnancy tests can be used even before you miss a period.

You can do a pregnancy test on a sample of urine collected at any time of the day. It doesn't have to be in the morning.

Where you can get a pregnancy test

You can buy pregnancy testing kits from pharmacists and some supermarkets. They can give a quick result and you can do the test in private.

The following places provide free pregnancy tests:

  • sexual health services
  • some young people's services – call the national sexual health helpline on 0300 123 7123 for details
  • Brook centres for under-25s – find your nearest Brook centre

You may also be able to get a pregnancy test free of charge from your GP.

How does a pregnancy test work?

All pregnancy tests detect the hormone human chorionic gonadotrophin (hCG), which starts to be produced around 6 days after fertilisation.

Most pregnancy tests come in a box that contains 1 or 2 long sticks. You pee on the stick and the result appears on the stick after a few minutes. All tests are slightly different, so always check the instructions.

Pregnancy test results

Home pregnancy tests are accurate as long as you follow the instructions correctly.

A positive test result is almost certainly correct. However, a negative test result is less reliable.

The result may not be reliable if you:

  • do not follow the instructions properly
  • take the test too early

Some medicines can also affect the results.

If you get a negative result and still think you're pregnant, wait a few days and try again. Speak to your GP if you get a negative result after a second test but your period has not arrived.

Continuing with the pregnancy

If you're pregnant and want to continue with the pregnancy, contact your GP or a midwife to start your antenatal care. You can use the pregnancy due date calculator to work out when your baby is due.

If you're not sure you want to be pregnant

If you're not sure about continuing with the pregnancy, you can discuss this confidentially with a healthcare professional. Your options are:

  • continuing with the pregnancy and keeping the baby
  • having an abortion
  • continuing with the pregnancy and having the baby adopted

As well as a GP or a nurse at your GP surgery, you can also get accurate, confidential information – from the age of 13 – from the following:

  • sexual health services
  • the MSI Reproductive Choices website
  • the British Pregnancy Advisory service website
  • the National Unplanned Pregnancy Advisory service website

All these services – including community contraceptive clinics – are confidential. If you're 13 or older, the staff won't tell your parents. They'll encourage you to talk to your parents, but they won't force you. 

If you're under 25 and would prefer advice specifically for young people, the sexual health charity Brook provides a range of services for young people. The Brook website contains information on pregnancy choices. You can also use the Ask Brook 24/7 service.

Video: Is the pregnancy test accurate?

In this video, a midwife explains when you can take a pregnancy test and how to do it properly.

Media last reviewed: 5 February 2020
Media review due: 5 February 2023

For women who have been trying to conceive, taking an early pregnancy test is a big moment. The whole “am I or aren’t I?” question is about to be answered and the emotions tied up with the big reveal cannot be overestimated.

But, repeatedly taking tests can get expensive and disappointing if they’re negative again and again. So, when is a realistic time to take an early pregnancy test to both minimise expense and disappointment? Here we explain everything you need to know about taking pregnancy tests…

How soon will a pregnancy test read positive?

Some pregnancy tests will be able to give you a positive result as soon as one day after a missed period. However, there are some pregnancy tests that can detect pregnancy early and will be able to show you the result 10 days after conception.

The best time to take a pregnancy test is one week after your missed period as this will show you the most reliable result. If you’re taking the pregnancy test early, do it in the morning when your urine is at its most concentrated so the test can more easily detect the HCG hormone. If you wait until one week after your period, you can take the pregnancy test any time of the day.

How early can you take a pregnancy test?

It’s recommended that you wait until at least the first day after your mission period. However, there are pregnancy tests available that can tell you if you’re pregnant as soon as 10 days after conception.

How soon after unprotected sex can I test for pregnancy?

Unfortunately, a pregnancy test will not show you are pregnant straight away as it takes your body time to release the hormone human chorionic gonadotropin (hCG), which shows up on pregnancy tests. It will be around 12-15 days after conception that you can test for pregnancy to get a reliable result.

What is an evaporation line on pregnancy test?

Evaporation lines on pregnancy tests are really common and can occur on any test. The evaporation line is the line that appears in the results window as the urine dries. It’s important to understand the difference between an evaporation line and a positive pregnancy test; you can do this by:

  • Always read the instructions to your pregnancy test
  • Read your pregnancy test result within the reaction time; which will be explained in your pregnancy test instructions – don’t read it after the time has passed

Can you get a false positive on a pregnancy test?

Can a pregnancy test be wrong? It’s rare to get a false positive on a pregnancy test, but yes, it can happen.

The causes of a false positive pregnancy test

A pregnancy test will only show positive if you have hCG in your system; there can be a number of causes of a false positive pregnancy test, including:

  • You were recently pregnant
  • You are taking fertility medications containing hCG
  • You have a medical condition such as rare ovarian cysts

Are pregnancy tests accurate? Can a pregnancy test be wrong?

Home pregnancy tests are accurate if you follow the instructions, although some are more sensitive and others are easier to use and interpret - so if funds allow, it may be worth buying a couple of different ones. If your period is late and a home test is positive you can consider yourself pregnant.

Remember though that if you test too early you may get a false negative result because not enough of the hormone has built up in your system. You should ideally wait four or five days before testing again.

It is also worth noting that in early pregnancy, before a fetal heartbeat can be detected on a scan, or where there is bleeding and there is uncertainty about whether the pregnancy is continuing, a blood test which measures the hCG levels can help. If they are rising sufficiently, they can point to a healthy pregnancy.

Can twins cause a false negative pregnancy test?

Although rare, it is possible for a twin or multiple pregnancy to cause a false negative pregnancy test due to the levels of hCG being very high. If you are seeing a negative pregnancy test but are experiencing pregnancy symptoms, speak to your GP.

How to do a pregnancy test

Whilst each pregnancy test will come with its own instructions, here is a basic step-by-step guide to taking a pregnancy test. Please remember to always read the instructions from your specific pregnancy test.

  • Remove the pregnancy test strip from any packaging and take off the cap (if there is one)
  • Place the absorbent tip of the test into your urine stream; if you are uncomfortable doing this you can collect your urine in a cup and place the pregnancy test within it for the designated time
  • It’s important to keep the pregnancy test pointing downwards throughout the test
  • Lay the pregnancy test flat, facing upwards
  • Wait the designated time for the result (based on the instructions)
  • Read the results

Is a faint line on a pregnancy test positive?

Yes – it doesn’t matter how faint the line is, if you have a line on your pregnancy test you are pregnant.

How do pregnancy tests work?

Home pregnancy tests detect the presence of the pregnancy hormone hCG (Beta Human Chorionic Gonadotropin), in your urine. Your body starts to produce hCG when a fertilised egg implants in your uterus and is secreted by the cells which will go on to form your baby's placenta. It can usually be detected in your urine from about 6 to 14 days after fertilisation. When you decide to test, try not to drink too much beforehand as it could dilute these levels. Some tests may recommend that you use the first urine of the day as levels of hCG become more concentrated in your urine overnight.

Types of pregnancy tests available

  • Sensitivity - Some pregnancy tests can detect hCG at a lower concentration than others, which means they can tell you're pregnant even when you have only a small amount of hCG in your system. Read the information that comes in the test box. Concentrations of hCG are reported in milli-International Units (mIU) per millilitre. A test with a sensitivity of 20 mIU/ml will be able to confirm a pregnancy earlier than one that needs a concentration of 50 mIU/ml.
  • Method - For many tests you simply have to pee on a test stick. For others you may have to catch your urine in a small cup and dip a testing strip into your sample. Or a dropper may be provided to place a small sample into a testing well.
  • Result - Some tests show pink or blue lines on the test strip. Others reveal a plus or minus sign or change the colour of your urine sample. Digital tests display the words "pregnant" or "not pregnant" in a window and some give an estimate of how many weeks ago you conceived.

Where to buy a pregnancy test

You don’t need a prescription for a pregnancy test. They are widely available in chemist shops and supermarkets, and you can also buy them online.

Which pregnancy test is the best?

You can find our round-up of the best pregnancy tests, here…