Can implantation bleeding start the day after intercourse

When you’re actively trying to get pregnant, those two weeks between ovulation and a positive home pregnancy test (or your period) can seem much longer. If you’re like most women, you’ll spend them hyper-aware of every ache, twinge and craving your body has, wondering whether it’s an early sign of pregnancy.

One of the most telltale symptoms of pregnancy is bleeding. If you do have some light spotting, does it mean anything?

While it can be hard to tell, many women who go on to have healthy, normal pregnancies have what’s called implantation bleeding around the time that their embryo lodges itself into the side of the uterus.

What is implantation bleeding?

Implantation bleeding is light bleeding or spotting that occurs between seven and 14 days after fertilization.

After ovulation and at the moment an egg is successfully fertilized by a sperm in a fallopian tube, the embryo starts dividing and growing. At this time, the inner lining of the uterus, called the endometrium, starts to change. It's already been thickening throughout the menstrual cycle, but it’ll need to grow and mature even more to protect and nourish an embryo.

Around five to six days after fertilization, the quickly growing embryo has moved down the fallopian tube and into the uterus. It’s starting to need more nutrients, and the endometrium has filled in enough to support it.

Next, the embryo attaches itself to the endometrium, where it becomes reliant on a mother’s body — for the first time — for nutrients and oxygen. When the embryo implants, it can disrupt tiny blood vessels in the spot it burrows into. This won’t cause any problems (the endometrium recovers!) but some women will experience light bleeding, from pinkish or red to brown discharge.

When does implantation bleeding happen?

So-called implantation bleeding will likely arrive earlier than your expected monthly menstrual period, usually around seven to 10 days after fertilization or conception.

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Signs of implantation bleeding

These are some of the most common implantation bleeding symptoms:

• Light bleeding or spotting that some women say is different from normal period bleeding because the blood is darker
• Mild cramping
• A woozy feeling
• Swollen breasts
• Headache

Implantation bleeding vs. period bleeding: How to tell the difference

Since implantation bleeding is a symptom that can often occur before you test positive on a pregnancy test, it can be hard to know whether light bleeding is an early sign of pregnancy or just normal spotting leading up to your period. And unfortunately, there’s no conclusive way to find out.

The best way to know whether you’re pregnant or not is to wait a few more days and take a pregnancy test. The timing of when you last had sex might also help you figure it out. If it’s been more than two weeks, it’s unlikely that any spotting you're having is implantation bleeding.

About a third of women who report having experienced implantation bleeding often describe it as distinct from their usual premenstrual spotting — some say the blood is darker and not as red compared with normal period blood. Others have mild cramping at the same time as the spotting.

But for many women, the two types of bleeding aren’t different at all. So you’re not alone if you assume that some spotting is implantation bleeding and get your period a few days later, or if you assume that implantation bleeding is normal spotting and end up being pregnant!

How long does implantation bleeding last?

Implantation bleeding usually only lasts one or two days. 

When to call the doctor

Light bleeding during pregnancy — even at times other than implantation — is often normal. Causes can include mundane things like irritation of the cervix following a pelvic exam, sex or infection of the vagina.

But because bleeding following a positive pregnancy test can sometimes be a sign of ectopic pregnancy, molar pregnancy or other early miscarriage, you should always call your medical provider if you experience it so you can talk through any other symptoms. Try not to worry too much though. Chances are good that if the bleeding is light and doesn't last long, everything is fine.

From the What to Expect editorial team and Heidi Murkoff, author of What to Expect When You're Expecting. What to Expect follows strict reporting guidelines and uses only credible sources, such as peer-reviewed studies, academic research institutions and highly respected health organizations. Learn how we keep our content accurate and up-to-date by reading our medical review and editorial policy.

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When a fertilized egg attaches to the wall of the uterus, where it can begin growing, some light spotting may occur. This is called implantation bleeding, and it can be one of the earliest clues that you are pregnant. Some women don’t experience this type of bleeding, and some simply don’t notice it. If it happens, it doesn’t indicate a problem with your pregnancy. If you’re wondering if you might be pregnant, take our Am I Pregnant? quiz for a little fun and grab a home pregnancy test.

Is It Implantation Bleeding or My Period?

It’s possible to mistake implantation bleeding for a very light and early period at first. However, there are some differences to pay attention to. Although every woman’s period is different, it’s still possible to guess that it's implantation bleeding by the color and amount of bleeding, and by where you are in your menstrual cycle, as well as by looking out for other early signs of pregnancy — more frequent bathroom trips, fatigue, and nausea (i.e., morning sickness).

These are the main signs and symptoms of implantation bleeding compared to a period:

• The amount of blood. Implantation bleeding isn’t heavy; it’s more like a discharge or light spotting that’s about a few drops of blood on your underwear.

• The color of the spotting. The blood from implantation is more of a pinkish or brown color, rather than a bright red some women normally see during a period.

When Does Implantation Bleeding Happen?

You may notice implantation bleeding around 10 to 14 days after conception, when a fertilized egg becomes attached to the lining of your uterus. Keep in mind that conception may not occur on the same day you had sex. Sperm can live as long as five days inside a woman’s reproductive tract, and conception might not occur for several days after sex.

Should I Take a Pregnancy Test During Implantation Bleeding?

You can take a home pregnancy test during implantation bleeding. Keep in mind that the pregnancy hormone human chorionic gonadotropin (or hCG) that pregnancy tests detect only starts being produced in your body the moment the fertilized egg is implanted in the uterus — which is the trigger for implantation bleeding. The earlier you take the test, the less hCG there is to detect, meaning that the test may not yet be accurate. If you have the patience to wait, you’ll get a more accurate test result if you wait until after the first day of your missed period.

If you get a positive test result, schedule an appointment with your healthcare provider to confirm your pregnancy. And you can get an estimate of when to expect your baby by using our handy tool to calculate your due date.

Should I See a Doctor?

Implantation bleeding is generally nothing to be concerned about, but it’s a good idea to talk to your healthcare provider about any bleeding you experience during pregnancy. Although light bleeding in early pregnancy can be totally normal, there are some reasons for bleeding in early pregnancy that need to be addressed immediately. These can include infection, miscarriage, or ectopic pregnancy.

Can implantation occur 1 day after intercourse?

Can implantation bleeding occur after intercourse?