Implantation bleeding is light bleeding that may happen about six to 12 days after conception. It may be caused by a fertilized egg implanting in the blood-rich lining of your uterus. Implantation bleeding can be an early sign of pregnancy, but some women mistake it for menstrual blood because it may happen around the time they expect their period. Show
Implantation bleedingImplantation bleeding is light bleeding that a small percentage of pregnant women have at about six to 12 days after fertilization. Here's the theory behind why it happens: After the sperm fertilizes the egg, it starts the three- or four-day trip from the fallopian tube to your uterus. During this time, it divides into hundreds of identical cells. Meanwhile, your ovaries release estrogen that causes the lining of the uterus (the endometrium) to thicken and develop more blood vessels. The uterine lining is preparing to host the quickly growing egg that will soon become an embryo. Once the egg enters the uterus, it's called a blastocyst, a tiny ball of several hundred cells. A day or two later, it begins burrowing into the blood-rich lining of your uterus, where it continues to grow and divide. As it burrows into the endometrium, the blastocyst may cause little blood vessels to burst, resulting in a small amount of vaginal bleeding. Implantation bleeding symptomsIn addition to light bleeding, some women also have these other implantation symptoms:
Note that these symptoms are no guarantee that you're pregnant – they can also be signs of ovulation or PMS. Taking a home pregnancy test is the best way to find out if you're pregnant. (Though you may have to wait a few more days to get an accurate result.) If you do get your period instead of a positive pregnancy test, and haven't yet scheduled a preconception visit with a midwife or doctor, now is a good time to do so. When does implantation bleeding occur?Implantation bleeding tends to occur during the week before you would expect your period, or about six to 12 days after conception. This is around the same time a fertilized egg would be attaching itself to the uterine lining. How long does implantation bleeding last?Unlike a regular menstrual period, implantation bleeding usually lasts no more than a day or two. This is the amount of time it takes for the fertilized egg to become implanted into the lining of the uterus. How common is implantation bleeding?By some estimates, about 15 to 25 percent of women experience implantation bleeding. Some women may think they’re having a light period when they see the spotting. They may not realize they're pregnant. How can I tell if it's implantation bleeding or my period?Here's how to tell whether your bleeding is more likely to be implantation bleeding or your period:
When to see a doctor for bleeding in early pregnancyIf you continue spotting even after a positive pregnancy test, or if you develop other symptoms (such as pelvic or abdominal pain, dizziness, or lightheadedness), call your provider immediately. You may need an exam to make sure you don't have an ectopic pregnancy. This happens when the fertilized egg grows outside the uterus, usually in a fallopian tube. (It's possible to have an ectopic pregnancy even if you don't get a positive result on a pregnancy test.) Bleeding or cramping in early pregnancy may also be a sign of an impending miscarriage. But many women spot in the first trimester for no apparent reason and go on to have a completely normal pregnancy. Learn more: Quiz: Am I pregnant? Video: What is implantation bleeding? Implantation bleeding can occur about 10-14 days after conception when the fertilized egg attaches to the interior lining of the uterus. This movement of the egg can result in light bleeding or spotting, which is completely normal and should not require any kind of medical attention. Generally, around a third of pregnant women will experience implantation bleeding. While similar in timing to a woman’s menstrual period, the two are different. Implantation bleeding is lighter than menstrual bleeding. Implantation Bleeding SymptomsImplantation bleeding is considered one of the early pregnancy symptoms (at least one of the first easily identifiable signs for a mother). Because implantation bleeding occurs near the time of her next period, many women are confused whether it is a possible pregnancy or a period. Here are other signs of implantation bleeding
(These can also be PMS symptoms or ovulation symptoms, so having these along with pinkish/brownish spotting does not guarantee that it has to do with pregnancy.) What Does Implantation Bleeding Look Like?Implantation bleeding looks a bit different from the average woman’s period. It is important to remember that not all women have the same kind of blood flow during their menstrual period. Some will have a heavier flow during their period while others may experience a bit more unpredictability. These are the key differences between implantation bleeding and a period:
How Long Does Implantation Bleeding Last?Implantation bleeding should last only between a couple of hours to three full days. If the bleeding you are experiencing is bright or dark red blood, lasts more than three days, and is a full flow in that you are filling up pads/tampons, it it very unlikely you are experiencing implantation bleeding. Women who are going through their first pregnancy will likely spot or bleed a little bit more than women who are used to the egg attachment. (It is similar to dental flossing of the gums as the first time the gum line is aggravated, it will bleed more, while subsequent times bleeding is lessened.) However, if your menstruation cycle is shorter than normal (< 3 days), you did not fill up pads or tampons, it was more pinkish/brownish than red, and you had less cramping than normal, it is possible that you are having implantation bleeding. Why Does Implantation Bleeding Happen?About 10-14 days after conception (when the sperm joins with the egg), the embryo will implant itself into the wall of the uterus. This movement may break down some blood vessels within the uterus wall and cause some bleeding. Menstruation occurs around 11-14 days after ovulation (when an egg is released & conception is possible), which is another reason why the two are often confused with one another. Some women may simply believe their period is a few days early. Implantation bleeding typically happens within the week before the expected period. For example, if you are sexually active and expect your period on January 25th, then you might question any spotting you have between Jan. 18th – Jan. 25th as possible implantation bleeding. It is not common that implantation bleeding would occur before this time or after a period is expected or missed. However, if one experiences ovulation early in the fertility window and the implantation process is quick, or one experiences ovulation late in the fertility window and the implantation process is slow, it is possible. Women know what their normal menstrual flow looks like, and as long as they are not on any kind of new medication (including birth control and emergency contraceptives) or have a change in stress level, then their menstrual blood flow, color, and consistency are usually the same. So, when this lighter, pink spotting occurs, it will appear a bit out of place. Implantation Bleeding ConcernsImplantation bleeding should not be a cause for concern and should pose no real risk to the developing baby. If you experience bleeding or spotting more than a few days after your missed period, it is not likely to be implantation bleeding. True pregnancy concerns rarely come from implantation and usually occur after the missed period. Though this post-implantation light bleeding during pregnancy is not considered normal, there are a few main reasons it may occur:
At least 50% of women that experience spotting/bleeding (other than implantation bleeding) will go on to have a normal, healthy pregnancy.
For women going through nausea/vomiting, dizziness, abdominal pain (especially one-sided pain), it is possible you are experiencing an ectopic pregnancy, so inform your doctor right away. Cramping is normal during pregnancy, yet if the level of pain during cramping increases, it is recommended to contact a doctor. Still Not Sure?If you are not sure which type of bleeding you are having, we recommend waiting three days after the bleeding/spotting stops before taking a pregnancy test. You are welcome to contact our toll-free helpline at 1-800-672-2296 to speak with a pregnancy educator. Often, taking a pregnancy test before the missed period or during implantation bleeding is just too soon for tests to offer conclusive results. Ideally, waiting a week after the spotting or missed period is most desirable as the results should prove more accurate. Next StepsImplantation bleeding is a sign of a potential pregnancy. If you have waited until after your period was due and taken a pregnancy test that delivered a negative result, there is a good chance you are not pregnant. Watching for implantation bleeding while trying to get pregnant is fine, but many women do not experience nor notice implantation spotting even when it does occur. Want to Know More?
Compiled using information from the following Medical sources: 1. March of Dimes: “Pregnancy Complications.” 2. National Institute of Child Health and Human Development: “What Are Some Common Signs of Pregnancy?” 3. American College of Obstetricians and Gynecologists: “Abnormal Uterine Bleeding,” “Early Pregnancy Loss.” 4. Norwitz ER, et al. Overview of the etiology and evaluation of vaginal bleeding in pregnant women. 5. Moore KL, et al. Answers to clinically oriented questions. In: Before We Are Born: Essentials of Embryology and Birth Defects. 8th ed. Philadelphia, Pa.: Saunders Elsevier; 2013. 6. Frequently asked questions. Pregnancy FAQ038. Bleeding during pregnancy. American College of Obstetricians and Gynecologists. https://www.acog.org/Patients/FAQs/Bleeding-During-Pregnancy 7. American College of Obstetricians and Gynecologists. Months 1 and 2. In: Your Pregnancy and Childbirth Month to Month. 6th ed. Washington, D.C.: American College of Obstetricians and Gynecologists; 2015. 8. Mayo Clinic FAQs |