Vaginal bleeding during pregnancy has many causes. Some are serious, and many aren't.

1st trimester

Possible causes of vaginal bleeding during the first trimester include:

  1. Ectopic pregnancy (in which the fertilized egg implants and grows outside of the uterus, such as in a fallopian tube)
  2. Implantation bleeding (which occurs about 10 to 14 days after conception when the fertilized egg implants in the lining of the uterus)
  3. Miscarriage (the spontaneous loss of pregnancy before the 20th week)
  4. Molar pregnancy (a rare occurrence in which an abnormal fertilized egg develops into abnormal tissue instead of a baby)
  5. Problems with the cervix, such as a cervical infection, inflamed cervix or growths on the cervix

2nd or 3rd trimester

Possible causes of vaginal bleeding during the second or third trimester include:

  1. Incompetent cervix (a premature opening of the cervix, which can lead to preterm birth)
  2. Miscarriage (before the 20th week) or intrauterine fetal death
  3. Placental abruption (when the placenta — which supplies nutrients and oxygen to the baby — separates from the wall of the uterus)
  4. Placenta previa (when the placenta covers the cervix, resulting in severe bleeding during pregnancy)
  5. Preterm labor (which might result in light bleeding — especially when accompanied by contractions, dull backache or pelvic pressure)
  6. Problems with the cervix, such as a cervical infection, inflamed cervix or growths on the cervix
  7. Uterine rupture, a rare but life-threatening occurrence in which the uterus tears open along the scar line from a prior C-section

Normal vaginal bleeding near the end of pregnancy

Light bleeding, often mixed with mucus, near the end of pregnancy could be a sign that labor is starting. This vaginal discharge is pink or bloody and is known as bloody show.

Causes shown here are commonly associated with this symptom. Work with your doctor or other health care professional for an accurate diagnosis.

From Mayo Clinic to your inbox

Sign up for free and stay up to date on research advancements, health tips, current health topics, and expertise on managing health. Click here for an email preview.

To provide you with the most relevant and helpful information, and understand which information is beneficial, we may combine your email and website usage information with other information we have about you. If you are a Mayo Clinic patient, this could include protected health information. If we combine this information with your protected health information, we will treat all of that information as protected health information and will only use or disclose that information as set forth in our notice of privacy practices. You may opt-out of email communications at any time by clicking on the unsubscribe link in the e-mail.

Jan. 20, 2022