How Soon After Unprotected Sex Can I Test for Pregnancy?

The wait to find out if you’re pregnant can be agonizing. So, let’s get into it: how soon after unprotected sex can I test for pregnancy?

Whether you’re TTC or trying not to, the interlude between unprotected sex and a reliable pregnancy test can feel long. And in that gap, a whole host of questions might be firing.

How soon after unprotected sex can I take a pregnancy test? Can I detect pregnancy in 3 days? 4? 5?

Let’s find out.

📝 In this article:

How long after sex can you take a pregnancy test?

Long story short, it’s recommended to wait to take a pregnancy test 2 weeks after sex if you’re trying to conceive, for the most accurate results. But why, why do we have to wait that long?

First, a quick spin around how pregnancy tests work. Basically, they’re on the lookout for a hormone called hCG (the long version of that is human chorionic gonadotropin). Your body releases hCG shortly after implantation.

Implantation happens like this: an egg is fertilized by an awaiting sperm and together they form a zygote. That zygote develops to an embryo and makes its way to your uterine wall where it implants in the hope of growing into an embryo, then a fetus, then a baby.

Home pregnancy tests are pretty accurate when the instructions are followed exactly. While not all pregnancy tests are created equal, most tests claim to be 99% accurate — as long as you take them at the right time in your cycle, the day after your next period is due, which is typically about 14 days after ovulation. [1]

If you take a pregnancy test too early, there’s a chance that you could get a false negative, because the hCG levels in your body haven’t had enough chance to build up.

There are also cases where you might get a false positive, although these are a bit rarer. If you were recently pregnant, or had an abortion or miscarriage, you may also get a "false positive" because there is still hCG in your system.

Testing very early can also pick up a chemical pregnancy, which is when the zygote is formed but does not implant or continue to a successful pregnancy. Interestingly, before today’s sensitive pregnancy tests were invented, many women had miscarriages without even realizing they were pregnant. These early miscarriages can often be mistaken for a period.

Is 7 days too early to test?

The short answer is yes. While implantation may have happened (usually around five to six days after conception), your body may still need some time to get its hCG levels up. (Anything above 10 mIU/mL is considered positive.)

Can we detect pregnancy in 3 days?

While you may not be able to get a conclusive test for a bit, it’s not uncommon to start experiencing symptoms as soon as a few days after conception. And if you’re not feeling anything, that doesn't mean anything either way. It’s totally normal not to have any symptoms until much later in your pregnancy.

One of the more common early pregnancy symptoms is implantation bleeding, which often looks more like spotting than a full-on period, and cramping. But you may have to wait until at least five or six days after having sex before implantation takes place.

Three days might be a little soon.

How soon after ovulation can you test?

If you’re trying to conceive, it’s recommended to take a pregnancy test 2 weeks after sex. That’s generally based on the assumption that you’ve had unprotected sex while you were ovulating (your fertile window) the point in your cycle when you’re most likely to conceive.

But waiting two weeks after ovulating to take a pregnancy test is also based on a 28-day cycle. So if your cycle is longer or shorter than 28 days, you may have more or less time to wait to take your pregnancy test.

The general rule of thumb is to take your pregnancy test the day after your period is usually due. Not sure when your next period is due? Sorry, but the wait’s going to be a bit longer — 21 days is your best bet for an accurate pregnancy test result.

When does implantation happen?

Implantation is a key moment in your pregnancy journey. The fertilized egg (now technically called a “blastocyst”) has traveled down your fallopian tube and attached itself to the wall of your uterus, preparing to grow into a baby.

But when does it happen? Well, every woman is different, but it typically takes a fertilized egg about 6 to 12 days to make it to your uterus and implant.

If we imagine, then, that you ovulate on day 14 of your menstrual cycle (which is about average for a 28-day cycle), and the egg is fertilized within 24 hours, implantation could take place between days 20 and 26. Quite a wide time frame!

How can you know that implantation has happened?

There are a few possible implantation symptoms that could give you a clue that the fertilized egg has set up home successfully.

For example, you might have some implantation bleeding. This looks like the kind of light spotting you may get at the beginning or end of your period and can be pinkish or brown in color. It might also be quite watery if it’s mixed with vaginal discharge.

Other potential symptoms of implantation include:

• Tender breasts
• Bloating
• Light cramping (it can feel like mild period cramps)
• Headaches
• Mood swings

Side note: If any of these symptoms sound familiar, that might be because they’re also common signs that your period is about to start. That can make identifying true implantation symptoms a little tricky (especially considering that implantation can happen right around the time you’re expecting your period).

Implantation can also happen without giving you any odd symptoms — a missed period might be the first sign that anything has changed.

How soon after implantation can I test?

It’s totally understandable if you’re impatient to take a pregnancy test after implantation bleeding (or any other symptom that’s making you suspicious). But when’s the best time to take a test?

To answer that, we first need to talk about how pregnancy tests work. Both a home pregnancy test (of the pee-on-a-stick variety) and a blood test at your doctor’s office work by detecting a hormone called human chorionic gonadotropin (hCG). Your body starts to produce hCG soon after implantation, and a pregnancy test will pick up on this once levels of the hormone are high enough. [2]

How quickly after implantation does hCG rise?

Your hCG levels start to rise right after implantation, and they should increase by at least 60% about every 48 to 72 hours in the first 4 weeks of pregnancy. [3]

How many days after implantation can you test?

When to test after implantation bleeding or another symptom depends on the type of pregnancy test. A blood pregnancy test is more sensitive, so it may be able to detect hCG about 6 to 8 days after conception — in other words, very soon after implantation.

A home pregnancy test, though, might only detect hCG about 10 days after conception — maybe four days or so after implantation. But for the highest chance of an accurate result (rather than a false negative), it’s best to leave taking a home pregnancy test until at least the day after your missed period.

Yep, even if you’ve noticed implantation symptoms. (We know — waiting is hard!)

What if I have implantation bleeding but a negative test?

It’s possible that either:

• You’ve taken the test too soon, and your hCG levels aren’t high enough to detect yet, or;
• What looks like implantation bleeding could actually be the start of your period.

That said, if you ever notice any abnormal vaginal bleeding or any bleeding in early pregnancy, it’s a good idea to check in with your healthcare provider.

What’s the earliest you can take a pregnancy test?

Well, here’s where it gets interesting. As it turns out, sometimes, you can get a positive pregnancy test mere days after conceiving.

The earliest we’ve heard from our Peanut mamas is 3 days after unprotected sex. But it’s still considered too early for an accurate result, so while you may get a positive 3 days after unprotected sex, there’s a chance it could be a false-positive.

Sorry to say, but it’s better to wait, if you can — the dreaded two-week wait.

How soon does hCG show up after sex?

If you are pregnant, hCG should show up very soon after implantation has taken place — about 10 days after unprotected sex. Because conception happens somewhere around the time you are ovulating (when an egg is released from your ovary) a helpful TTC marker is how many days past ovulation you are. If you’ve seen the acronym DPO, that’s what it stands for. So if you’re wondering when is the best time to take a pregnancy test, a good time is about 14 DPO.

And if that feels really confusing and/or you have no idea when you ovulated, the easiest is to wait until after your next expected period. If it doesn’t come, take a test. If you’re unsure of the result you get, take another one in a few days' time.

What cycle day did you get a positive pregnancy test?

It’s different for every mama, so we asked our Peanut community of moms-to-be how soon after unprotected sex they got their positive pregnancy test:

• “I got mine at 8 DPO, but I also went through fertility treatments and knew the exact date I ovulated and was tracking twice per day.” — Monica
• “I don’t know what cycle day it was but I was able to get one 5 days prior to my expected period. I noticed I was having to get up and pee a lot throughout the night, so I took one and it came out with a faint positive. I’ve taken several since then and I have had four positives on three different brands of pregnancy tests. I suggest using morning pee that’s usually when mine came out positive.” — Dee
• “Cycle day 32, 11 DPO.” — Sophie
• “Cycle day 33 5 days before my predicted period, 7 DPO (I have really long cycles).” — Brittani
• “Cycle day 32 for me was a BFN ‒ my period was 2 days late. Cycle day 36 ‒ BFP. I think I ovulated late as my positive was exactly 15 days after we BD'd the week after ovulation was due ‒ I didn't track ovulation.” — Edwina
• “The day after I was supposed to get my period. I tested the day of, as when I start it's always in the morning with my first pee. So I tested the day I was supposed to start and it was negative. My period didn't come so the day after I missed it, I tested again and got my faint positive.” — Angila
• “With my first, I was 14 DPO, with my second, I was 16 DPO.” — Naomi
• “I had a faint positive 8 DPO.” — Olivia
• “Faint lines at 10 DPO. Positive digital at 12 DPO. First morning urines. The lines have been getting darker since. I need to stop testing!!” — Nicki
• “With this pregnancy, 8 DPO faint and strong positive at 16 DPO.” — Victoria
• “9 DPO, day period was due.” — Rachel
• “I tested 12 DPO and got a really strong positive.” — Millie
• “I’m not sure exactly how many DPO, but it was 3 days before my expected period I have irregular periods.” — Queen
• “I took several 11-12 DPO and they were negative. Took one on the day my period was supposed to start and got a faint positive. Took a First Response and it was there but still faint in my opinion so I took a digital one and it read pregnant!” — Tori
• “Got a super faint positive at 10 DPO. Got really dark the day my period was due (14 DPO).” — Beth
• “I tested when I was two days late and it was positive!” — Jess
• “I got a positive at 7 DPO, no joke!” — Nora
• “I tested positive 8 days after my missed period.” — Tabitha
• “I got my positive 10 DPO (officially) but really 5 days past 5-day transfer (IVF) so I honestly was testing like from 3 or 4 days past transfer (no way possible to be clinically pregnant at that point).” — Alona
• “With both of mine I got my positive test 2 days before missed period.” — Ali

And if you’re looking for some help with surviving this time (the infamous TWW or Two Week Wait), we’ve got you covered.

We know, wondering how soon after unprotected sex you can take a pregnancy test can be super stressful.

But sometimes, it helps to know you’re not alone.

So join our Peanut community of other women who are TTC, share your story, and hear from other women who have been there.

We’re wishing you all the best — don’t forget to share your results on Peanut!