Implantation Bleeding or Early Miscarriage?

Pregnant African American woman holding her stomach in hospital
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Implantation bleeding is vaginal bleeding that occurs in some women during the first few weeks of pregnancy. Since so many women have unexplained spotting or light bleeding early in viable pregnancies, the theory is that harmless light bleeding can occur as the fertilized ​egg implants and the uterus begins to adjust to the pregnancy.

There's not a lot of research about the exact reasons why some women have this bleeding and others do not, but implantation bleeding is no cause for concern and does not affect the viability of the pregnancy.

Similarly, not having implantation bleeding should not be considered a cause for worry.

Timing of Implantation Bleeding

The time when implantation bleeding occurs is typically within the first two weeks after fertilization, up to the time that the woman expects her menstrual period. Note that implantation bleeding is an imprecise term; although the fertilized egg implants in the uterus about eight to 10 days after ovulation, light bleeding can occur at other times in early pregnancy and a doctor may still refer to the bleeding as "implantation bleeding."

Due to the timing, implantation bleeding could also be mistaken for an extremely light menstrual period in some women. If you have unusually light bleeding around the time of your menstrual period and that does not turn into a heavier, normal flow, consider taking a pregnancy test.

Some women have light menstrual flows normally and may not realize that this time they are in fact pregnant.

They may engage in behaviors that could affect the developing fetus, such as drinking, smoking, taking medications or unprescribed drugs.

It can also make it more difficult to know when you became pregnant, as you may think it occurred the following month and the implantation bleeding was your regular period.

All the more reason to take a pregnancy test if you have an unusually light menstrual period and have any chance that you could be pregnant. A few spots of blood or a light flow should not be taken as proof that you are not pregnant.

Implantation Bleeding or Early Miscarriage?

Distinguishing implantation bleeding from early miscarriage bleeding can be confusing as well. In general, bleeding associated with an impending miscarriage or chemical pregnancy may begin as spotting but then turn into a heavier flow with visible clots and a dark red color (similar to a menstrual period).

In contrast, implantation bleeding may appear as a brown or lighter colored discharge without clots with a lighter flow that lasts only a few hours to a few days.

Neither rule is universally true, however, and the best way to determine the cause of early pregnancy bleeding is to visit your doctor for hCG blood tests or an early pregnancy ultrasound.

Vaginal bleeding can also occur due to an infection in the pelvic cavity or urinary tract. Some women experience bleeding after intercourse. Discuss any bleeding with your doctor.


  • American Pregnancy Association, "Bleeding During Pregnancy." Aug 2015.
  • Mayo Clinic, "Bleeding During Pregnancy: What It Happens, What to Do." Mayo Clinic Health Information May 2007.

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