Implantation bleeding is light bleeding from the vagina that happens in some women 10 to 14 days after conceiving a baby. You may think it’s just a light period, but it’s an early sign of pregnancy. It’s not dangerous, and you don’t need treatment. But heavy bleeding (more than you’d have with a typical period) can be a sign of a problem. Call your doctor if you bleed a lot, with or without fever, chills, or have cramps that get worse. After a sperm fertilizes your egg, the combination becomes an embryo.
It travels to your uterus, where it implants itself into the lining. Sometimes, as the embryo attaches, it causes a little bleeding. This usually happens about the time you would have your period. You may even confuse it with your period and not realize you’re pregnant. Implantation bleeding is normal and doesn’t mean you or your baby will have problems. Implantation bleeding tends to happen before you notice morning sickness. You might have: It’s probably implantation bleeding if you have some of the other signs of early pregnancy, including: If you’re not sure whether you’re having implantation bleeding or your period, take a pregnancy test or talk to your doctor. Unlike most periods, it usually stops after 1 or 2 days. It will stop on its own. If you're worried that you've bled a lot, call your doctor. They may want to know how much blood you saw and what color it was. Many things can cause bleeding in pregnant women, some of them harmless and some serious. If you’re bleeding a lot, with or without pain or cramping at any time, call your doctor.What Is Implantation Bleeding?
When Does Implantation Bleeding Happen?
Implantation Bleeding Symptoms
How Long Does Implantation Bleeding Last?
Implantation Bleeding Treatment
Other Causes of Bleeding During Pregnancy
If you’re pregnant and see blood in your underwear, it may be caused by: Sex. Hormonal and physical changes may be to blame for this. It should stop on its own. Fibroids and polyps. Your doctor might do some tests to check for these growths on your uterus. Cervical problems. Conditions like infection or growths on your cervix can also cause bleeding. Infection. Sexually transmitted diseases like trichomoniasis can cause light bleeding as well as more serious problems. Starting treatment as soon as possible will keep your baby healthy. Ectopic pregnancy. This is when an embryo implants outside your uterus. You may have bleeding with pain and cramps. It’s dangerous and needs medical care right away. Miscarriage. About 15% of known pregnancies end during the first few months. Most women bleed and cramp afterward. Call
your doctor right away if you know that you're pregnant and you have these symptoms. Call your doctor if the bleeding doesn’t stop after a few days or if you’re worried about how much you are bleeding. When to See a Doctor
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.
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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