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What causes bleeding in pregnancy?

Medically reviewed by Last updated on Nov 14, 2022.

Official answer


What causes bleeding in pregnancy?

Vaginal bleeding and cramping is not unusual in the first trimester of pregnancy, as the fertilized egg implants and begins to grow inside the uterus. You may get light bleeding, spotting, cramps or stomach pain. Light bleeding can also occur during the other stages of pregnancy. Light bleeding and spotting during pregnancy may be caused by:

  • Implantation bleeding – causing some cramping pain or light bleeding when the fertilised egg implants in the uterus lining.
  • Bleeding from the cervix – sexual intercourse or a pelvic exam, for example, can cause bleeding from the cervix due to the increased blood flow from more blood vessels developing in this area.
  • Vaginal or uterine infection - Vaginal infections later in pregnancy are common due to changing hormones. They may cause bleeding and other problems, so it’s important to seek treatment if you suspect you have a vaginal infection..
  • A ‘show’ - loss of a blood-streaked mucus plug can occur at the end of your pregnancy and may indicate labor is about to start.

Heavier bleeding, or bleeding later in pregnancy, can indicate something more serious such as:

  • Miscarriage – a loss of pregnancy before 20 weeks gestation (growth). Miscarriages are most common in the first 12 weeks of pregnancy and are usually a singular event. Many women go on to have a successful pregnancy after a miscarriage.
  • Ectopic pregnancy – this is when a pregnancy implants outside of the uterus, usually in the fallopian tube. Ectopic pregnancies produce symptoms within the first 12 weeks of pregnancy and can be life-threatening
  • Molar pregnancy – occurs during early pregnancy when the tissue surrounding a fertilised egg develops abnormally and does not progress into a proper pregnancy.
  • Problems with the placenta - Placental abruption, placenta previa, or placenta accreta are the three main problems. Most cases are picked up in a routine ultrasound, though sometimes it is not until after birth that a problem is discovered. Your healthcare provider will monitor the situation and have a labour plan that is best for you and baby.
  • Pre-term labour - is labour starting before 37 weeks of pregnancy. This will be managed by your healthcare provider. Treatment and delivery options will be based on what is best for you and your baby.

What should I do?

It is best to contact your obstetrician–gynecologist (ob-gyn) or other healthcare professional straight away if you have any concerns about bleeding or cramping at any time during pregnancy.


National Health Service UK (NHS). Vaginal bleeding in pregnancy. Reviewed 20 March, 2020. Available at: [Accessed 25 November, 2020].

The American College of Obstetricians and Gynecologists (ACOG). Bleeding during pregnancy. September, 2019. Available at: h [Accessed 25 November, 2020].

First cry parenting. Common Vaginal Infections During Pregnancy. 22 May, 2018. Reviewed 20 August, 2020. Available at: [Accessed 25 November, 2020].

Department of Health, Western Australia. Bleeding or pain in early pregnancy. Available at: [Accessed 25 November, 2020].

What to expect. Spotting or Bleeding During Pregnancy. Reviewed 20 March, 2020. Available at: [Accessed 25 November, 2020].

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