Does implantation bleeding occur after a missed period

Implantation bleeding is light bleeding that may happen about six to 12 days after conception. It may be caused by a fertilized egg implanting in the blood-rich lining of your uterus. Implantation bleeding can be an early sign of pregnancy, but some women mistake it for menstrual blood because it may happen around the time they expect their period.

Table of Contents Show

Implantation bleeding
Implantation bleeding symptoms
When does implantation bleeding occur?
How long does implantation bleeding last?
How common is implantation bleeding?
How can I tell if it's implantation bleeding or my period?
When to see a doctor for bleeding in early pregnancy

Implantation bleeding

Implantation bleeding is light bleeding that a small percentage of pregnant women have at about six to 12 days after fertilization. Here's the theory behind why it happens:

After the sperm fertilizes the egg, it starts the three- or four-day trip from the fallopian tube to your uterus. During this time, it divides into hundreds of identical cells. Meanwhile, your ovaries release estrogen that causes the lining of the uterus (the endometrium) to thicken and develop more blood vessels. The uterine lining is preparing to host the quickly growing egg that will soon become an embryo.

Once the egg enters the uterus, it's called a blastocyst, a tiny ball of several hundred cells. A day or two later, it begins burrowing into the blood-rich lining of your uterus, where it continues to grow and divide. As it burrows into the endometrium, the blastocyst may cause little blood vessels to burst, resulting in a small amount of vaginal bleeding.

Implantation bleeding symptoms

In addition to light bleeding, some women also have these other implantation symptoms:

Light cramping (less than with a normal period)
Nausea
Breast tenderness
Lower back pain
Mood swings
Headaches

Note that these symptoms are no guarantee that you're pregnant – they can also be signs of ovulation or PMS. Taking a home pregnancy test is the best way to find out if you're pregnant. (Though you may have to wait a few more days to get an accurate result.)

If you do get your period instead of a positive pregnancy test, and haven't yet scheduled a preconception visit with a midwife or doctor, now is a good time to do so.

When does implantation bleeding occur?

Implantation bleeding tends to occur during the week before you would expect your period, or about six to 12 days after conception. This is around the same time a fertilized egg would be attaching itself to the uterine lining.

How long does implantation bleeding last?

Unlike a regular menstrual period, implantation bleeding usually lasts no more than a day or two. This is the amount of time it takes for the fertilized egg to become implanted into the lining of the uterus.

How common is implantation bleeding?

By some estimates, about 15 to 25 percent of women experience implantation bleeding. Some women may think they’re having a light period when they see the spotting. They may not realize they're pregnant.

How can I tell if it's implantation bleeding or my period?

Here's how to tell whether your bleeding is more likely to be implantation bleeding or your period:

Amount of blood. Implantation bleeding is a lot lighter than a typical period. It's usually just a little spotting.
Length of time. Most women bleed for three to seven days during their period. Implantation bleeding often lasts only one to three days.
Color. Menstrual blood is usually bright red or dark red, but implantation bleeding tends to be a light pink, brown, or rust discharge.
Clotting. Many women bleed enough during their period that some of the blood clots or becomes like a gel. Implantation bleeding is too light to clot.

When to see a doctor for bleeding in early pregnancy

If you continue spotting even after a positive pregnancy test, or if you develop other symptoms (such as pelvic or abdominal pain, dizziness, or lightheadedness), call your provider immediately.

You may need an exam to make sure you don't have an ectopic pregnancy. This happens when the fertilized egg grows outside the uterus, usually in a fallopian tube. (It's possible to have an ectopic pregnancy even if you don't get a positive result on a pregnancy test.)

Bleeding or cramping in early pregnancy may also be a sign of an impending miscarriage. But many women spot in the first trimester for no apparent reason and go on to have a completely normal pregnancy.

Learn more:

Quiz: Am I pregnant?

Video: What is implantation bleeding?

Implantation bleeding is light spotting that some people may mistake for an early period.

Implantation bleeding occurs when a fertilized egg implants in the uterine lining. The bleeding is usually light and may last a few days.

In this article, we explain what implantation bleeding looks like and how people can distinguish it from menstruation. We also explain when to take a pregnancy test and see a doctor.

Implantation bleeding may initially resemble the start of a menstrual period. However, while menstrual flow will usually get progressively heavier, implantation bleeding will not.

On a pad: Implantation bleeding is usually light and, therefore, should not soak a pad. However, the bleeding may be enough to be noticeable, and a person may wish to wear a pantyliner.
When using the toilet: A person may see a small amount of blood in the toilet or on a piece of toilet paper when they use the bathroom.
On a tampon: Ideally, if a person suspects implantation bleeding, they will not use a tampon. A tampon can introduce bacteria into the vagina, increasing the risk of a vaginal infection. However, if using a tampon, the bleeding should not soak it enough to require multiple changes.

The appearance of implantation bleeding can vary from person to person, but it is usually light pink or a rusty brown.

If a person has very regular periods, and implantation bleeding occurs about 2 weeks after fertilization, the bleeding may initially seem like the start of a period. However, there are some key differences. These include the following:

In some people, implantation bleeding may occur earlier than an expected period.
Implantation bleeding does not usually last as long as a period.
A menstrual period tends to be heavier than implantation bleeding, which is usually light spotting.

If the bleeding persists beyond a few days, it is not likely to be implantation bleeding.

If someone is unsure whether their bleeding is pregnancy-related or a period, they can take a home pregnancy test.

These tests detect the presence of the human chorionic gonadotropin (hCG) hormone. The body starts to make hCG once the fertilized egg has implanted in the uterus. Therefore, the production of this hormone will begin just after the time when implantation bleeding might occur.

While home pregnancy tests have become increasingly sensitive to hCG, waiting until the first day after a missed period is likely to yield a more accurate result.

Learn about how and when to take a pregnancy test here.

Implantation bleeding occurs during the first trimester, usually about 1–2 weeks after a sperm fertilizes an egg.

The following is a typical fertilization cycle timeline:

A person will usually ovulate (release an egg from the ovary) about 14 days before their next menstrual period starts.
Once the egg is released, a sperm must fertilize it within 12–24 hours.
If fertilization does not take place, the cycle will continue, and a period will usually occur in 2 weeks.
If fertilization does occur, the fertilized egg will remain in the fallopian tube for several days before moving toward the uterus.
When the fertilized egg reaches the uterus, it can implant into the uterine lining.

There are other potential causes of bleeding in early pregnancy. An estimated 15–25% of people experience some form of bleeding in the first trimester.

Learn more about bleeding in the first trimester here.

Implantation bleeding is not a cause for concern. The bleeding is usually light and does not last very long.

However, other symptoms may indicate other issues, such as an ectopic pregnancy or pregnancy loss. These symptoms include:

lightheadedness
shoulder pain
unexplained stomach or pelvic pain
vaginal bleeding that persists for several days
weakness

These symptoms can indicate a potential emergency and require immediate medical attention.

Implantation bleeding is usually shorter and less heavy than menstrual bleeding. If a person is unsure which one they are experiencing, they can wait a few days and then take a pregnancy test.

If at any time during a confirmed pregnancy, the bleeding becomes heavy or accompanies cramping pain, medical attention is necessary.