Implantation Bleeding vs. Your Period: Decoding this Early Sign of Pregnancy

If you’re trying to get pregnant, the two weeks between ovulation and your scheduled period can be excruciating. If and when your period arrives, you know you have to start all over again. But did you know that blood in your underwear could actually mean you conceived? Instead of Aunt Flow it could be her pregnancy-related cousin: implantation bleeding.

What Is Implantation Bleeding?

Most women ovulate halfway through their menstrual cycle, and if you don’t get pregnant then, you’ll get your period about two weeks after that. If a sperm does successfully fertilize the egg you released at ovulation, you have conceived. This newly created embryo will then travel to your uterus and burrow itself into the lining, if all goes according to plan. When this occurs, the embryo may agitate the blood cells in your lining and cause blood to be released from your body. The apparent release of that blood is known as implantation bleeding and it is an early pregnancy symptom.  

There are a few ways you can distinguish implantation bleeding from your period:

  • Timing: Implantation bleeding happens six to 14 days after conception. It typically happens before your period would normally arrive.
  • Color: Implantation bleeding is often pink or brown, instead of bright red.
  • Amount of blood: Implantation bleeding produces spotting, not a heavy flow. It usually lasts one to three days. That’s because the embryo has displaced only a small portion of your uterine lining. When you get your period, on the other hand, you shed the whole thing.

How Common Is Implantation Bleeding?

As many as one in four pregnant women may experience implantation bleeding. In its run down of pregnancy symptoms, the National Institute of Child Health and Human Development cites research that shows 25 percent of pregnant women experience some spotting that is lighter in color than normal menstrual blood and which occurs about six to 12 days after conception. You can’t say for certain that each instance of early bleeding is caused by implantation, but it is a common explanation.

As many as one in four pregnant women may experience implantation bleeding.

Typically, this type of early bleeding is not something to worry about. I spoke to Dr. Emily Harville and Dr. Allen Wilcox, co-authors of a paper on vaginal bleeding in very early pregnancy. In their study, nine percent of women with clinical pregnancies reported bleeding in the first eight weeks of pregnancy. And about 85 percent of these pregnancies continued to a live birth. “These data suggest that a few days of bleeding in early pregnancy is not a rare event, and furthermore that such bleeding has little relevance to the ultimate success of the pregnancy,” they concluded.

As far as the exact timing of this pregnancy symptom, the study found that bleeding tended to occur around the time when women would expect their periods, although rarely on the day of implantation. Dr. Harville, who researches reproductive questions at Tulane University, told me: “We had very specific information on when implantation was occurring, and ‘implantation bleeding’ did not usually occur on the actual day of implantation.” This finding suggests that there may be a delay between implantation and when the bleeding appears, which makes sense since the blood would have to travel through your body. It could also indicate that other causes can explain bleeding in very early pregnancy.

Other Causes of Bleeding in Early Pregnancy

Besides your period or implantation bleeding, there may be other explanations for bleeding in early pregnancy.  The American College of Obstetricians and Gynecologists explains that the cervix may bleed more easily during pregnancy because more blood vessels are developing in this area. Sexual intercourse or a pelvic exam could also trigger harmless light bleeding. A subchorionic hemorrhage, or blood clot on the wall of the uterus, may also be to blame. Such blood clots typically resolve themselves.

Finally, complications like an ectopic pregnancy (when the fertilized egg implants outside of the uterus) or threatened miscarriage due to chromosomal problems can also lead to early bleeding. If you see blood and suspect you might be pregnant, it’s always a good idea to contact your doctor. Now you know: don’t just assume it’s your period.

Featured image by courtesy of Cora

Get our weekly digest for advice on sex, periods, and life in a female body

OTHER TOPICS

Continue the conversation

12 Comments

  • Light flow, I normally have a heavy flow pad is full in an hour or 2. Flow is really light and a week early with no clots. Really nervous and trying not to think about it

    Reply
    • That’s going on with me right now I’m always on time with my period but I got my period a week early and I have a light flow slight cramping no clots

      Reply
  • Light flow usually have heavy flow a week early with a light flow

    Reply
  • I believe I may be pregnant I was ovulating the first two weeks of March an had unprotected sex with my partner my period was scheduled for March 19 an well I believe implantation bleeding has accured I only bleed the 19 an 20 of March an didn’t have the rest of my period …. I took a test but it was to early at the time to test ….

    Reply
  • I started spotting on the 3th of this month for a couple hours. My period was suppose to come on the 15th When it did come it was a light flow I’m usually heavy and it’s started on the 10th. What should I do?????

    Reply
  • usually, I hv 32 to 34 days cycle, usually my period starts on the 6th or 8th of every month, I missed my period on February, I thought it was pregnancy, but on the 6th of March, it came out, it was supposed to start on d 6th of this month, but it didnt come, through out that period I was having serious cramps, nipple pain that changed to heaviness in d breast, now 46 days later, my period started today 20th April, plz I need advise on what to do and help.

    Reply
    • This sounds like PCOS to me, you should definitely go see your doctor to confirm or refute this for your own price of mind.

      Reply
  • I am a week early on my period and I am very worried.. I have been doing so much research because I am having so many pregnancy symptoms until now. At first I was just spotting but it’s very heavy now, and my period is very regular so if anyone knows anything I would love the advice..

    Reply
  • Hi my period came on a week early and only stayed on for 2 days i was cramping a little then normally I be ball up in a knott when my period do come on but this period was weird plus my period normally stay on for 5days and me and my husband have been trying

    Reply

Leave a Reply

Your email address will not be published. Required fields are marked *