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How Soon After Unprotected Sex Can I Test For Pregnancy?

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Whether you’re trying to conceive or have suffered a mishap with your contraception choice, the wait between intercourse and receiving an accurate and reliable test result can feel like a lifetime.

To accurately collect the results, here is everything you need to know about how soon after unprotected sex you can test for pregnancy.

How Soon After Unprotected Sex Can I Test For Pregnancy?

Understanding Your Menstrual Cycle

In order to figure out if you are pregnant or not, this means you need to know the ins and outs of your menstrual cycle.

This can quickly become very confusing and easily become a minefield of numbers and dates that simply make no sense. Let’s take a look at some key factors with regard to your cycle and pregnancy.

Ovulation is when your ovaries create a mature egg, ready to be released into the fallopian tube to then be fertilized by the sperm.

It can be hard to figure out when your ovulation window will be so you can aim or avoid this key point of fertility in your cycle. Generally, women will ovulate anywhere from 11-21 days into their cycle.

The egg will be able to survive for 24h hours at this stage, meaning if you have unprotected sex during this point in your cycle it is very likely the sperm will travel up to fertilize the egg, this is then called fertilization.

It is important to know it can take up to 6 days for the sperm and egg to join together, as this can mean another delay in getting the timing of your test right.

Although this egg will now be fertilized, it doesn’t actually make its way from the fallopian tube and into your uterus for around another 7 days. This stage is referred to as implantation as the egg will attach onto the lining of your uterus.

So in short, pregnancy would not start on the day you have sex. It could be around another 2-3 weeks before your pregnancy would begin which is why it is important to wait before taking a pregnancy test to ensure you get an accurate result based on your body’s HCG levels.

How Soon After Unprotected Sex Can I Test For Pregnancy?

Generally, the most common first sign of a possible pregnancy will be a missed period, although some cycles can be anywhere from 24-38 days long, meaning if you do find you are 1-2 days late then this shouldn’t be a cause for concern.

If you find your periods tend to be regular and predictable then you can test from the first day of your missed period. If your periods are often late or scattered for any reason, then as a general rule wait 3 weeks after unprotected sex to test.

Some home testing kits claim to offer accurate results several days before your missed period.

However, you should remember that the accuracy of these is questionable in the days before your period and therefore we suggest waiting until your period is late to test

Home Pregnancy Tests

Many women prefer the convenience of home testing kits as they are a quick and easy way to get accurate results based on the HCG levels in your urine. The further along you are in your pregnancy, the higher the levels of this hormone will be as they double every 72hrs. 

Human chorionic gonadotropin (HCG) is a hormone produced by the cells surrounding a growing embryo in the placenta after implantation. The levels of this hormone peak between 8-11 weeks of pregnancy and then decline going forwards.

When the HCG travels through the test paper of your pregnancy test, it will attach to antibodies present in the test. These then transfer the blue dye which appears on the test to give you a positive reading.

What is a False Positive Pregnancy Test?

A very rare 1% of all pregnancy results are what is known as a false positive. This is when for several reasons, your test stick provides a positive reading even though you are not actually pregnant. 

Reasons for this may be a recent miscarriage or abortion creating the presence of HCG hormones. In this case, it is best to wait before attempting to gain another reliable reading as it can take from 9-35 days for your HCG levels to drop back down to pre-pregnancy levels. Other reasons for a false positive pregnancy test may be:

  • Medications such as fertility treatments include HCG to trigger the release of a mature egg.
  • Medical Conditions such as UTIs, kidney disease, or ovarian cysts.
  • Chemical Pregnancy, is a miscarriage that happens before the fifth week of pregnancy where the embryo implants but never takes hold in your uterus.

What is a False Negative Pregnancy Test?

Why You May Be Days Late But Have A Negative Pregnancy Test

False-negative results are much more common, with one study showing up to 48% of the recorded tests were wrongly negative! The most common reasoning for this is simply taking the test too early for your HCG levels to be high enough to produce a positive test.

It can also be due to other basic errors such as incorrect usage of the pregnancy test, a faulty test, or too much or too little HCG present in the urine.

This is why most medical professionals suggest you take a pregnancy test using the first pee you take when you wake up in the morning.

This is because your levels will be at their most concentrated and show up better on your pregnancy test.

After around 8-11 weeks of pregnancy, your levels will drop, meaning it is important if you have a strong feeling you are pregnant to get further testing done from your doctor.

Preventative Measures

There are some options available if you act fast after unprotected sex and don’t wait until it’s too late. Preventing pregnancy from developing means you usually will have to follow one of these methods within a certain amount of days (usually around 5).

  • An emergency contraceptive pill which is also known as the morning-after pill needs to be taken within 5 days of unprotected sex happening in order to work. Some types may require a prescription and others are available to purchase over the counter, all depending on the type you choose. 
  • Levonorgestrel pills such as Plan B One-Step, AfterPill, and Aftera are available to purchase over the counter from most pharmacies and drugstores but work best when taken within 3 days of unprotected sex, but you can take them up to 5 days after too.
  • The second option is only available through a prescription provided by a doctor or nurse and is a ulipristal acetate pill. These are to be taken as soon after unprotected sex as possible, but definitely within 5 days of happening for the most accurate result.

It is important to know whichever option you choose will not affect your chances of pregnancy in the future and may only cause short-term harmless side effects.

You should never take two types of contraceptives within 5 days of each other as this can create the opposite effect and cause you more harm than good.

Frequently Asked Questions

Can a pregnancy test detect at 1 week?

Female hand with red fingernails holding positive pregnancy test

Most tests on the market provide an accurate result from the first day of your missed period, so you should try to wait up to a week after your missed period to get the most accurate result possible.

What are the most common signs of pregnancy?

The most common symptom of pregnancy will be a missed period. Many women also report fatigue, tender breasts, and nausea in the very early stages of their pregnancy.

What happens 4 days after ovulation?

Around this time, the fertilized egg should still be traveling down the fallopian tube into your uterine cavity. This will then implant into the lining of your uterus and receive the nutrients it needs to grow a placenta.

Can you feel pregnant by touching your stomach?

Many women report feeling a cramping sensation as an early sign of pregnancy which can be confusing and regularly mistaken as period cramps. This is usually caused by the implantation of the egg and the expansion of your uterus.

The Final Thought

As a general rule, waiting until the first day of your missed period is the best way to get an accurate and reliable pregnancy test reading, but if this still leaves you scratching your head, wait 72hrs and test again as if you are pregnant.

Your HCG levels will have doubled and therefore are more likely to show up on a test.

Hi, I'm Emma and I'm a mother to 5 beautiful children aged from 1 to 21 years old- life is hectic! I have learned so much along the way, not only from my own children but also through my professional life. In my positions as a Childminder and Teaching Assistant, I have studied Child Development and The Early Years Developing Practice. I wish to share all of this knowledge and help you with your own parenting journey!