Implantation bleeding is light spotting that some people may mistake for an early period. Show
Implantation bleeding occurs when a fertilized egg implants in the uterine lining. The bleeding is usually light and may last a few days. In this article, we explain what implantation bleeding looks like and how people can distinguish it from menstruation. We also explain when to take a pregnancy test and see a doctor. Implantation bleeding may initially resemble the start of a menstrual period. However, while menstrual flow will usually get progressively heavier, implantation bleeding will not.
The appearance of implantation bleeding can vary from person to person, but it is usually light pink or a rusty brown. If a person has very regular periods, and implantation bleeding occurs about 2 weeks after fertilization, the bleeding may initially seem like the start of a period. However, there are some key differences. These include the following:
If the bleeding persists beyond a few days, it is not likely to be implantation bleeding. If someone is unsure whether their bleeding is pregnancy-related or a period, they can take a home pregnancy test. These tests detect the presence of the human chorionic gonadotropin (hCG) hormone. The body starts to make hCG once the fertilized egg has implanted in the uterus. Therefore, the production of this hormone will begin just after the time when implantation bleeding might occur. While home pregnancy tests have become increasingly sensitive to hCG, waiting until the first day after a missed period is likely to yield a more accurate result. Learn about how and when to take a pregnancy test here.
Implantation bleeding occurs during the first trimester, usually about 1–2 weeks after a sperm fertilizes an egg. The following is a typical fertilization cycle timeline:
There are other potential causes of bleeding in early pregnancy. An estimated 15–25% of people experience some form of bleeding in the first trimester. Learn more about bleeding in the first trimester here. Implantation bleeding is not a cause for concern. The bleeding is usually light and does not last very long. However, other symptoms may indicate other issues, such as an ectopic pregnancy or pregnancy loss. These symptoms include:
These symptoms can indicate a potential emergency and require immediate medical attention. Implantation bleeding is usually shorter and less heavy than menstrual bleeding. If a person is unsure which one they are experiencing, they can wait a few days and then take a pregnancy test. If at any time during a confirmed pregnancy, the bleeding becomes heavy or accompanies cramping pain, medical attention is necessary. 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 How do I know if it's implantation bleeding or my period starting?A: Unfortunately, there's no way to tell the difference between implantation bleeding and menstrual bleeding. Implantation occurs 6-12 days after conception, which is around the same time you may be expecting your monthly period, and both can produce the same amount of bleeding.
How many days before your period did you have implantation bleeding?Implantation bleeding is generally light and short, just a few days' worth. It usually occurs 10-14 days after conception, or around the time of your missed period. However, vaginal bleeding has been reported anytime in the first eight weeks of pregnancy. Spotting is also common before the start of a menstrual period.
Can you mistake implantation bleeding for period?Implantation bleeding typically occurs within days of conception, when the embryo (or blastocyst) attaches to the uterine lining. Some people mistake it for their regular period because it can look similar and occur near the time you'd expect your normal cycle.
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