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.
A person may also notice early pregnancy symptoms alongside implantation bleeding. These may include:
However, some people may not have implantation bleeding at all, just as they may not have many, if any, noticeable early pregnancy symptoms.
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.
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.
Implantation bleeding is not a cause for concern. The bleeding is usually light and does not last very long.
- shoulder pain
- unexplained stomach or pelvic pain
- vaginal bleeding that persists for several days
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.