Bleeding During Pregnancy: Implantation Bleeding or Miscarriage

Illustration of signs of implantation bleeding

Verywell / Catherine Song

If you are pregnant, it can become very worrisome to experience vaginal bleeding. One of the less recognized causes of vaginal bleeding during early pregnancy is implantation bleeding, which can present like a light period. Implantation bleeding may be an indication that you are pregnant and is not usually a cause for alarm.

However, there are several concerning causes of bleeding during pregnancy, such as miscarriage, ectopic pregnancy, and infection. For these reasons, is important to get medical attention if you have bleeding during pregnancy.

Characteristics of Implantation Bleeding

Implantation bleeding happens during the very early stages of pregnancy. It appears as a smear of blood on your underwear or toilet paper a few days before or after the time when you can first test positive on a pregnancy test. Implantation bleeding, which occurs around ten days after fertilization, signals that a fertilized egg has implanted, or attached to the wall of a woman's uterus.

Implantation bleeding typically occurs within one to two weeks after fertilization (conception), which is often close to the time that you would expect your monthly period. Due to this timing, implantation bleeding could be mistaken for an extremely light menstrual period, especially for women who normally have light menstrual flows.

Implantation bleeding does not affect the viability of a pregnancy and is not a cause for concern. Similarly, not having implantation bleeding is also OK and should not worry you. But it is important to recognize that it is a sign of pregnancy and not a period. If you know you are pregnant, you can discontinue activities that may affect your developing baby, such as smoking, drinking alcohol, or taking certain medications.

If you have unusually light bleeding around the time of your menstrual period and the bleeding does not turn into a heavier, normal flow, it's a good idea to take a pregnancy test. A few spots of blood or a light flow should not be taken as a period or as a sign that you are not pregnant—you could be.

Implantation Bleeding vs. Early Miscarriage

If you experience bleeding when you are trying to get pregnant, or when you know you are pregnant, you are likely to be very concerned. Distinguishing implantation bleeding from the bleeding of an early miscarriage can be confusing.

In general, bleeding associated with an impending miscarriage or chemical pregnancy (a nonviable pregnancy) may begin as spotting and then turn into a heavier flow with visible clots and a dark red color, similar to a heavy menstrual period. Cramping and passing tissue through the vagina are other signs of a miscarriage.

In contrast, implantation bleeding may appear as a brown or lighter colored discharge without clots. It is a lighter flow that lasts only a few hours to a few days. The best way to determine the cause of early pregnancy bleeding is to visit your doctor. You are likely to have an hCG blood test or an early pregnancy ultrasound, in addition to a thorough medical history and physical examination.

An hCG blood test measures the pregnancy hormone, human chorionic gonadotropin (hCG), which is made by the placenta after the fertilized egg implants into the lining of the uterus. With ultrasound, a gestational sac becomes visible around five weeks after your last menstrual cycle if you are pregnant, and an embryo or fetal pole is visible at the end of the sixth week.

Other Causes of Early Pregnancy Bleeding

Some women who are pregnant also experience light bleeding after sex or after a pelvic exam, due to the development of blood vessels in the cervix. Or, vaginal bleeding during pregnancy may be a sign of an infection of the cervix, vagina, or urinary tract.

Vaginal bleeding may also be a sign of an ectopic pregnancy, which occurs when a fertilized egg implants into one of the fallopian tubes instead of the lining of the uterus. Other symptoms may include pain in the abdomen, pelvis, or even the shoulder, but sometimes vaginal bleeding is the only sign.

An ectopic pregnancy is a dangerous condition because the fallopian tube can tear open and cause internal bleeding, so it is important to seek medical attention if you are experiencing these symptoms. The fertilized egg in the fallopian tube needs to be removed with surgery or medication.

A Word From Verywell

If you are experiencing any vaginal bleeding during pregnancy, you should contact your doctor. While it's natural to worry about a possible miscarriage, there could be a number of reasons why you experienced spotting in early pregnancy, including harmless causes like implantation bleeding or bleeding after having sex. Your doctor can identify the cause of your bleeding and make a treatment plan if necessary. 

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4 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Suganya K, Subbarayan LM. Maternal and perinatal outcomes in women with first trimester vaginal bleedingInt J Reprod Contracept Obstet Gynecol. 2019;8(11):4320. doi:10.18203/2320-1770.ijrcog20194850

  2. American College of Obstetricians and Gynecologists. Bleeding during pregnancy.

  3. American College of Obstetricians and Gynecologists. Routine tests in pregnancy.

  4. American College of Obstetricians and Gynecologists. Ectopic pregnancy.

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