Table of ContentsView AllTable of ContentsWhen It OccursWhat It Looks LikeWhy It HappensOther Causes of Bleeding
Table of ContentsView All
View All
Table of Contents
When It Occurs
What It Looks Like
Why It Happens
Other Causes of Bleeding
Implantation bleeding is spotting or light bleeding that occurs when a fertilized egg attaches itself to the uterine lining (endometrium). It can happen about six to 12 days after conception. While implantation bleeding can be an early sign of pregnancy, not everyone who’s pregnant experiences it.
Approximately 15% to 25% of those who become pregnant will have bleeding in the first trimester. Implantation bleeding is a normal symptom that doesn’t require any medical attention.However, there are important signs to watch for that can indicate something serious.
This article discusses when implantation bleeding happens and why it occurs. It also covers what implantation bleeding looks like and instances of bleeding that may require medical attention.
Verywell / Jessica Olah
When Does Implantation Bleeding Occur?
Implantation bleeding occurs at a specific point during the menstrual cycle—typically between days 20 and 24, assuming you have a 28-day cycle.
It only occurs when a fertilized egg attaches itself to the uterine lining. Still, someone can be pregnant and experience no implantation bleeding at all.
This is not the only type of bleeding you may experience. Ovulation bleeding is light bleeding or spotting that occurs when an egg is released from the ovary. Period bleeding occurs if a fertilized egg does not implant in the wall of your uterus after ovulation and the lining sheds.
You may assume implantation bleeding is the start of your period since the timing of both are similar.
Your menstrual cycle begins on the first day of your period. If you experience light bleeding 20 to 24 days after the first day of your last period, it might be implantation bleeding. Bleeding that begins 28 days after the first day of your last period is more likely to be period bleeding.
Normal vs. Irregular Periods
What Implantation Bleeding Looks Like
Implantation bleeding can last from a few hours to a few days. It may come and go or remain constant during that time.
Some symptoms that may accompany implantation bleeding include:
Though implantation bleeding and period bleeding can be confused with one another due to when they occur, there are differences between the two.
Implantation BleedingLight pink to rust colorLighter in consistency (may look like discharge)Can be light or only noticeable when you wipeMenstrual FlowMostly bright red or dark redCan be thick, stringy, or jelly-likeCan be light to heavy
Implantation BleedingLight pink to rust colorLighter in consistency (may look like discharge)Can be light or only noticeable when you wipe
Light pink to rust color
Lighter in consistency (may look like discharge)
Can be light or only noticeable when you wipe
Menstrual FlowMostly bright red or dark redCan be thick, stringy, or jelly-likeCan be light to heavy
Mostly bright red or dark red
Can be thick, stringy, or jelly-like
Can be light to heavy
Implantation bleeding is one of the earliest signs of pregnancy. Since these two causes of bleeding can be confused,taking a pregnancy testis the best way to know if you are pregnant.
Will a pregnancy test be positive during implantation bleeding?If you are experiencing implantation bleeding, you are pregnant. However, a pregnancy test may not show a positive result (yet). Pregnancy tests look for the hormone hCG. It must reach a certain level to be reliably detected. Production of hCG starts after implantation occurs, so it may take a few days for your body to make enough to generate a positive pregnancy test result.
Will a pregnancy test be positive during implantation bleeding?
If you are experiencing implantation bleeding, you are pregnant. However, a pregnancy test may not show a positive result (yet). Pregnancy tests look for the hormone hCG. It must reach a certain level to be reliably detected. Production of hCG starts after implantation occurs, so it may take a few days for your body to make enough to generate a positive pregnancy test result.
Why Implantation Bleeding Happens
When an egg is released from an ovary (usually once per month), ovulation occurs. At this point, the egg travels through the fallopian tube.
If implantation does not occur, the egg and uterine lining are shed during the menstrual period.
After dividing into about 100 cells, the egg becomes what is known as a blastocyst. The uterine lining has many blood vessels, so when the fertilized egg (blastocyst) pushes into the lining, bleeding can occur.
The Cervix in Early Pregnancy
Other conditions, some serious, can cause vaginal bleeding. Possible causes of bleeding include:
Medical Emergencies
Early miscarriage and ectopic pregnancy are two possible reasons for vaginal bleeding. These are medical emergencies, so you should be aware of the symptoms and seek medical care immediately if you experience them.
Early Miscarriage
Early miscarriage, which can occur five weeks after ovulation, can cause vaginal bleeding.
Unlike implantation bleeding, earlymiscarriage bleedingtypically causes:
The pain and bleeding of miscarriage can be greater than during your period. Know, however, that bleeding doesn’t occur with all miscarriages. Pain or cramping during pregnancy is enough to warrant medical attention.
Ectopic Pregnancy
Bleeding can also occur during an ectopic pregnancy—when a fertilized ovum implants outside of the uterus.
Symptoms of an ectopic pregnancy include:
These tend to occur six to eight weeks after your last period.
When to See a Healthcare Provider
Non-Urgent Conditions
Some possible causes of non-urgent bleeding include:
If bleeding occurs more than a few days after you expect to get your period, it likely is not implantation bleeding.
Have a conversation with your healthcare provider if you are experiencing any symptoms that concern you.
Summary
Implantation bleeding typically happens between days 20 and 24 of your menstrual cycle (assuming a 28-day cycle). Blood will appear light in consistency and color (pinkish to brown) and bleeding may last from a few hours to a few days.
There are other causes of bleeding during pregnancy and some (like ectopic pregnancy or miscarriage) need immediate medical treatment. Be sure to tell your healthcare provider about any bleeding you experience if you believe you may be pregnant, and seek emergency care if you experience abnormal heavy bleeding or pain.
5 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.American College of Obstetricians and Gynecologists.Bleeding during pregnancy.Committee opinion no 700: methods for estimating the due date.Obstetrics & Gynecology. 2017;129(5):e150-e154. doi:10.1097/aog.0000000000002046American Pregnancy Association.What is Implantation Bleeding?Cedars Sinai.Ectopic Pregnancy.Hendriks E, MacNaughton H, MacKenzie MC.First trimester bleeding: evaluation and management.Am Fam Physician. 2019;99(3):166-174.
5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.American College of Obstetricians and Gynecologists.Bleeding during pregnancy.Committee opinion no 700: methods for estimating the due date.Obstetrics & Gynecology. 2017;129(5):e150-e154. doi:10.1097/aog.0000000000002046American Pregnancy Association.What is Implantation Bleeding?Cedars Sinai.Ectopic Pregnancy.Hendriks E, MacNaughton H, MacKenzie MC.First trimester bleeding: evaluation and management.Am Fam Physician. 2019;99(3):166-174.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
American College of Obstetricians and Gynecologists.Bleeding during pregnancy.Committee opinion no 700: methods for estimating the due date.Obstetrics & Gynecology. 2017;129(5):e150-e154. doi:10.1097/aog.0000000000002046American Pregnancy Association.What is Implantation Bleeding?Cedars Sinai.Ectopic Pregnancy.Hendriks E, MacNaughton H, MacKenzie MC.First trimester bleeding: evaluation and management.Am Fam Physician. 2019;99(3):166-174.
American College of Obstetricians and Gynecologists.Bleeding during pregnancy.
Committee opinion no 700: methods for estimating the due date.Obstetrics & Gynecology. 2017;129(5):e150-e154. doi:10.1097/aog.0000000000002046
American Pregnancy Association.What is Implantation Bleeding?
Cedars Sinai.Ectopic Pregnancy.
Hendriks E, MacNaughton H, MacKenzie MC.First trimester bleeding: evaluation and management.Am Fam Physician. 2019;99(3):166-174.
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