Can you confuse implantation bleeding with a period

When you’re actively trying to get pregnant, those two weeks between ovulation and a positive home pregnancy test (or your period) can seem much longer. If you’re like most women, you’ll spend them hyper-aware of every ache, twinge and craving your body has, wondering whether it’s an early sign of pregnancy.

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What is implantation bleeding?
When does implantation bleeding happen?
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Signs of implantation bleeding
Implantation bleeding vs. period bleeding: How to tell the difference
How long does implantation bleeding last?
When to call the doctor
Understanding the Menstrual Cycle
How Do You Tell if It’s Implantation Bleeding or a Regular Period?
When to Consult a Doctor

One of the most telltale symptoms of pregnancy is bleeding. If you do have some light spotting, does it mean anything?

While it can be hard to tell, many women who go on to have healthy, normal pregnancies have what’s called implantation bleeding around the time that their embryo lodges itself into the side of the uterus.

What is implantation bleeding?

Implantation bleeding is light bleeding or spotting that occurs between seven and 14 days after fertilization.

After ovulation and at the moment an egg is successfully fertilized by a sperm in a fallopian tube, the embryo starts dividing and growing. At this time, the inner lining of the uterus, called the endometrium, starts to change. It's already been thickening throughout the menstrual cycle, but it’ll need to grow and mature even more to protect and nourish an embryo.

Around five to six days after fertilization, the quickly growing embryo has moved down the fallopian tube and into the uterus. It’s starting to need more nutrients, and the endometrium has filled in enough to support it.

Next, the embryo attaches itself to the endometrium, where it becomes reliant on a mother’s body — for the first time — for nutrients and oxygen. When the embryo implants, it can disrupt tiny blood vessels in the spot it burrows into. This won’t cause any problems (the endometrium recovers!) but some women will experience light bleeding, from pinkish or red to brown discharge.

When does implantation bleeding happen?

So-called implantation bleeding will likely arrive earlier than your expected monthly menstrual period, usually around seven to 10 days after fertilization or conception.

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Signs of implantation bleeding

These are some of the most common implantation bleeding symptoms:

Light bleeding or spotting that some women say is different from normal period bleeding because the blood is darker
Mild cramping
A woozy feeling
Swollen breasts
Headache

Implantation bleeding vs. period bleeding: How to tell the difference

Since implantation bleeding is a symptom that can often occur before you test positive on a pregnancy test, it can be hard to know whether light bleeding is an early sign of pregnancy or just normal spotting leading up to your period. And unfortunately, there’s no conclusive way to find out.

The best way to know whether you’re pregnant or not is to wait a few more days and take a pregnancy test. The timing of when you last had sex might also help you figure it out. If it’s been more than two weeks, it’s unlikely that any spotting you're having is implantation bleeding.

About a third of women who report having experienced implantation bleeding often describe it as distinct from their usual premenstrual spotting — some say the blood is darker and not as red compared with normal period blood. Others have mild cramping at the same time as the spotting.

But for many women, the two types of bleeding aren’t different at all. So you’re not alone if you assume that some spotting is implantation bleeding and get your period a few days later, or if you assume that implantation bleeding is normal spotting and end up being pregnant!

How long does implantation bleeding last?

Implantation bleeding usually only lasts one or two days.

When to call the doctor

Light bleeding during pregnancy — even at times other than implantation — is often normal. Causes can include mundane things like irritation of the cervix following a pelvic exam, sex or infection of the vagina.

But because bleeding following a positive pregnancy test can sometimes be a sign of ectopic pregnancy, molar pregnancy or other early miscarriage, you should always call your medical provider if you experience it so you can talk through any other symptoms. Try not to worry too much though. Chances are good that if the bleeding is light and doesn't last long, everything is fine.

From the What to Expect editorial team and Heidi Murkoff, author of What to Expect When You're Expecting. What to Expect follows strict reporting guidelines and uses only credible sources, such as peer-reviewed studies, academic research institutions and highly respected health organizations. Learn how we keep our content accurate and up-to-date by reading our medical review and editorial policy.

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Menstrual Cycle
- Understanding the Menstrual Cycle
vs. Regular Period
- How Do You Tell if It’s Implantation Bleeding or a Regular Period?
When to Call a Doctor
- When to Consult a Doctor
Guide
- How Can I Tell if It's Implantation Bleeding? Topic Guide

Implantation bleeding is bleeding that occurs about two to three weeks after fertilization. Blood from implantation bleeding tends to be pink or rusty brown in color, light flow with no clotting and it lasts for one to three days accompanied by other symptoms.

Implantation bleeding is bleeding that occurs in women typically when the fertilized egg (embryo) attaches itself to the lining of the uterus. This usually occurs between 6 and 12 days after conception (successful joining of an egg and a sperm). Implantation bleeding may often be mistaken for a regular period because it may look similar and occur around the same time as a woman’s regular period. Hence, women should be able to recognize whether vaginal bleeding is a result of implantation bleeding and know when to seek medical attention. If a woman suspects that her bleeding is a result of implantation bleeding and not a regular period, she should do a home pregnancy test (urine pregnancy test [UPT]) and consult a doctor. Implantation bleeding occurs in around 25 percent of pregnancies.

Facts that distinguish implantation bleeding from menses or miscarriage are as follows.

Bleeding lasts for a short span
Blood is brown, black, or pink
A very little amount of bleeding
Very mild cramping or no cramping at all
No clots

Understanding the Menstrual Cycle

During every menstrual cycle, an egg develops and is released from one of the ovaries (ovulation). At the same time, the lining of the uterus becomes thicker due to hormonal changes. If pregnancy does not occur, the thickened lining (endometrium) of the uterus sheds through the vagina accompanied by bleeding. Bleeding usually lasts for three to eight days, and this is known as menstruation or period. The menstrual cycle usually lasts between 24 and 38 days but is typically 28 days long.

Phases of the menstrual cycle:

Menstruation: It is the period of shedding of the uterine lining accompanied by bleeding. Levels of estrogen and progesterone are low.
The follicular phase: It is the time between the first day of the period and ovulation. Estrogen levels increase as an egg prepares to be released and the uterine lining builds up.
Ovulation (Day 14): It is the release of the egg from the ovary. It is the mid-cycle.
The luteal phase: It is the time between ovulation and the start of menstruation. The body prepares for a possible pregnancy. Progesterone peaks and then drops if pregnancy does not occur, resulting in menstruation or period bleeding.

How Do You Tell if It’s Implantation Bleeding or a Regular Period?

Implantation bleeding is very short-lived, unlike a regular period. It usually only lasts for 24-48 hours, which is the amount of time taken for the fertilized egg to get implanted into the lining of the uterus. Ovulation occurs between Day 14 and 16 and fertilization occurs between Day 18 and 20 of the menstrual cycle. Implantation usually occurs between Day 24 and 26 of the menstrual cycle. Implantation bleeding may occur two to seven days after fertilization. The blood in implantation bleeding is typically dark brown or black, indicating that it’s older blood. Sometimes, it may be red or pink. Blood flow is not heavy, unlike a regular period. Additionally, there may only be some light spotting or a few drops to slightly larger amounts in many cases.

Characteristics of a regular period

Usually lasts for three to seven days
Blood in the first two to three days of bright red
Bleeding is heavy and decreases toward the end of the period
More painful cramping
Cramps may begin few days before bleeding and continue for two to three days

Characteristics of implantation bleeding

Usually only lasts for 24-48 hours
Bleeding is light and usually brown, pinkish or black, and rarely reddish
Milder uterine cramping compared with regular periods or no cramping at all

When to Consult a Doctor

If a woman suspects that her bleeding is a result of implantation bleeding and not a regular period, she should do a home pregnancy test (urine pregnancy test [UPT]) and consult a doctor. Implantation bleeding occurs in around 25 percent of pregnancies and is typically not dangerous. However, women should deal with any bleeding during pregnancy with caution. They should consult a doctor for the same if bleeding is very little or there is just spotting. Although not all bleeding is an emergency or a sign of complications, the doctor would advise tests, such as an ultrasound, that are important to evaluate the cause. Bright red blood indicates active bleeding, and it is an emergency, especially if there are blood clots and pain. This could be a sign of something serious such as a miscarriage.