What is vaginal bleeding during pregnancy?

Vaginal bleeding during pregnancy is the discharge of vaginal blood that some women experience at any stage of pregnancy.

Vaginal bleeding:

  • Can occur early or late in pregnancy;
  • Is more common during the first trimester of pregnancy;
  • Is estimated to affect around 25% of women during their first trimester of pregnancy, [1 ] and;
  • Has multiple possible causes, not all of which are serious.

Many women who experience vaginal bleeding during their pregnancy go on to deliver a normal and healthy baby.

Baby in utero; foetus in utero.The anatomy of a baby and mother during pregnancy. 

Trimester

One third of a period of time. Often used to describe the three stages of pregnancy, in which each trimester is about three months long.

1. Deutchman M. Tubay A.T. and Turok D. (2009) First trimester bleeding. American family physician 79:985-992.

Causes

Implantation

It is common for women to experience some light vaginal bleeding during the first few weeks of their pregnancy. This type of vaginal bleeding is called implantation bleeding and is associated with the attachment of the fertilised egg to the uterus lining.

Vaginal bleeding associated with implantation:

  • Usually happens around the time the next period would normally have been due;
  • May range in colour from red to brown, and;
  • Usually lasts a few days before resolving.

Miscarriage

Vaginal bleeding that occurs in the first 20 weeks of pregnancy is often associated with miscarriage, or a loss of the pregnancy. Miscarriage is a common cause of vaginal bleeding during early pregnancy. The exact cause of miscarriage is not always clear, but certain risk factors include:

Ectopic pregnancy

During the first 12 weeks of pregnancy, vaginal bleeding may be a sign of an ectopic pregnancy. In an ectopic pregnancy, the fertilised egg has implanted outside the uterus. Vaginal bleeding that is caused by ectopic pregnancy can be associated with cramping, abdominal pain and light-headedness. Ectopic pregnancy is a less common cause of vaginal bleeding.

Hormone changes

Changes in hormone levels during pregnancy can affect the surface of the cervix. Such changes may make the cervix more vulnerable to damage and some pregnant women may experience vaginal bleeding after having sex.

Fibroids

Benign growths in the lining of the uterus, called fibroids, can be the cause of some cases of vaginal bleeding during pregnancy. If the placenta embeds where there is a fibroid, it can cause vaginal bleeding.

Cervical polyps

Cervical polyps are growths that occur in the inner lining of the uterus. They can be round or oval and range in size from a few millimetres to a few centimetres. There may be one or several present and are usually benign, but they can be associated with some miscarriages.

The bloody show

A mucus plug is normally found in the cervix during pregnancy, sealing the cervical canal. This plug may be cloudy, clear, thick and sticky, but as the cervix becomes thin towards the end of pregnancy, blood is released into the cervix, causing the mucus plug to become bloody. As labour draws closer, the plug becomes increasingly bloody. Vaginal bleeding may occur nearer the time of labour, when this mucus plug, called 'the bloody show', drops away and is passed through the vagina.  

Low-lying placenta

During pregnancy, the placenta develops at the site where the egg has attached to the uterus, which can sometimes occur in the lower part of the uterus. In these situations, the placenta is often pulled upwards and away from the cervix into a more normal position as the pregnancy develops and the uterus expands. Women whose placenta remains low-lying after 20 weeks of pregnancy are referred to as having a low-lying placenta (also known as placenta praevia). It can be a cause of vaginal bleeding after 28 weeks of pregnancy. This type of vaginal bleeding is usually painless and associated with bright red blood.

Vasa praevia

In a normal pregnancy, the blood vessels of the umbilical cord and placenta are protected inside the amniotic sac. If you experience vasa praeiva, where the blood vessels are instead found at the surface of membranes where they have no insulation. Rupturing of the blood vessels can cause vaginal bleeding. 

Uterine rupture

A uterine rupture is an abnormal splitting open of the uterus, which causes the baby to be partially or fully expelled into the abdomen. This is a very rare cause of vaginal bleeding during pregnancy that is often accompanied by severe abdominal pain and tenderness.

Placental abruption

Placental abruption is when a part of or all of the placenta separates from the wall of the uterus before the birth. It can cause heavy vaginal bleeding that may be accompanied by other symptoms, including abdominal and lower back pain, a tender and hard uterus, fetal distress and frequent uterine contractions.

Benign

Not leading to cancerous growth. Not harmful.

Cervix

The lower part of the uterus, leading out into the vagina.

Diabetes

A metabolic disorder that is caused by problems with insulin secretion and regulation and which is characterised by high blood sugar levels. Also known as diabetes mellitus.

Placenta

The organ that forms within the uterus of a pregnant woman to provide the fetus with nourishment from the blood supply of the mother.

Uterus

The hollow organ of the female reproductive system that is responsible for the development of the embryo and fetus during pregnancy. Also known as the womb.

1. Deutchman M. Tubay A.T. and Turok D. (2009) First trimester bleeding. American family physician 79:985-992.

Signs and symptoms

Some women may experience vaginal bleeding during their pregnancy without any other symptoms. For women who do experience vaginal bleeding with other symptoms, such symptoms may include:

  • Cramps;
  • Pain;
  • Dizziness;
  • Fatigue, and;
  • Excessive thirst.

These symptoms may vary, depending on the cause of the vaginal bleeding and the stage of pregnancy during which they happen.

1. Deutchman M. Tubay A.T. and Turok D. (2009) First trimester bleeding. American family physician 79:985-992.

Methods for diagnosis

Medical history and physical examination

Taking a detailed medical history will form part of your doctor's diagnosis. 

Some questions that may be asked may include:

  • How far along is the pregnancy?
  • When did the bleeding start? Is it intermittent or constant?
  • What colour is the blood?
  • Is there any pain accompanying the bleeding?
  • Is there any dizziness, nausea or vomiting?

A careful pelvic examination may also be performed, depending on the stage of pregnancy and the specific symptoms accompanying the vaginal bleeding. Vaginal examination is sometimes avoided at late stages of pregnancy due to risks of triggering further bleeding.

Diagnostic tests

Blood tests

Common blood tests may include:

  • Full blood count;
  • Blood type assessment, and;
  • Measuring the level of pregnancy hormone, human chorionic gonadotrophin (hCG).

Urine test

A urine test can be used to check for a urinary tract infection or sexually transmitted infections such as gonorrhoea and chlamydia.

Ultrasound

An ultrasound will be conducted to ensure the baby remains healthy in the uterus and to see if there are other possible causes of the bleeding.

Full blood count

A blood test that examines the blood, either by using a microscope or an automated machine, to determine the number of red blood cells, white blood cells and platelets.

Uterus

The hollow organ of the female reproductive system that is responsible for the development of the embryo and fetus during pregnancy. Also known as the womb.

1. Deutchman M. Tubay A.T. and Turok D. (2009) First trimester bleeding. American family physician 79:985-992.

Types of treatment

It is important to visit your doctor if you experience vaginal bleeding during pregnancy. Depending on the cause, it may require treatment in hospital. Initial treatment is aimed at ensuring the mother and baby remain well. The mother may be given intravenous fluids to keep her hydrated. Additional treatments are aimed at stopping the bleeding and will depend on the underlying cause.

Miscarriage

Once a miscarriage has started, it is often difficult to save the fetus. Treatment is aimed to help minimise blood loss and the chance of infection, deliver the contents of the uterus, and emotionally support the mother and family during this difficult period.

Placental abruption / low-lying placenta

Women with placental abruption or low-lying placenta may be kept in hospital for further monitoring, until bleeding resolves. If bleeding does not resolve, or worsens, and the pregnancy is near term, the baby is often delivered by a caesarean section.

Vasa praevia

For women whose vasa praevia is diagnosed before the onset of labour, a caesarean section is scheduled for a few weeks prior to the due date. For women whose vasa praevia is not diagnosed until labour has commenced, the baby is delivered by an emergency caesarean section.

Uterine rupture

Diagnosis of uterine rupture warrants immediate delivery, with surgical repair to the uterus to follow. If the mother's blood loss is severe, she is administered intravenous (IV) fluids. Only in severe cases is a blood transfusion given.

Placenta

The organ that forms within the uterus of a pregnant woman to provide the fetus with nourishment from the blood supply of the mother.

Uterus

The hollow organ of the female reproductive system that is responsible for the development of the embryo and fetus during pregnancy. Also known as the womb.

1. Deutchman M. Tubay A.T. and Turok D. (2009) First trimester bleeding. American family physician 79:985-992.

Potential complications

The potential complications associated with vaginal bleeding during pregnancy may vary, depending on the stage of pregnancy and the severity of the condition. These include potential risks to the unborn baby, such as fetal distress, premature birth, and even death. Risks to the mother include the need for blood transfusions, emergency caesarean section, and potentially death.

Hysterectomy

Hysterectomy is the surgical removal of the uterus. This may be required if vaginal bleeding is severe and cannot be stopped with other treatments. 

Uterus

The hollow organ of the female reproductive system that is responsible for the development of the embryo and fetus during pregnancy. Also known as the womb.

1. Deutchman M. Tubay A.T. and Turok D. (2009) First trimester bleeding. American family physician 79:985-992.

Prognosis

Vaginal bleeding during pregnancy is common, especially during the first trimester. The outcome of this condition varies widely, depending on the cause and the stage of pregnancy.

Trimester

One third of a period of time. Often used to describe the three stages of pregnancy, in which each trimester is about three months long.

1. Deutchman M. Tubay A.T. and Turok D. (2009) First trimester bleeding. American family physician 79:985-992.

Prevention

The exact cause of most cases of vaginal bleeding during pregnancy is not clearly understood. You may be able to reduce your risk by following some simple measures that may include:

1. Deutchman M. Tubay A.T. and Turok D. (2009) First trimester bleeding. American family physician 79:985-992.