Gestational thrombocytopenia is a drop in platelet count during pregnancy. It does not cause symptoms and resolves naturally. However, thrombocytopenia in pregnancy may sometimes indicate more serious health issues.

Platelets, or thrombocytes, are blood cells that cause blood to clot and prevent excessive bleeding. Pregnancy may cause some physical changes that affect the amounts of platelets and other components present in blood.

Thrombocytopenia occurs in 5–10% of pregnancies, and 75% of these cases are due to gestational thrombocytopenia. Other types of thrombocytopenia can also occur in pregnant people.

Gestational thrombocytopenia is not usually dangerous and commonly resolves quickly once the person is no longer pregnant. However, in some cases, a low platelet count during pregnancy can indicate a more serious issue such as preeclampsia or HELLP syndrome (hemolysis, elevated liver enzymes, and low platelets).

Read on to learn more about gestational thrombocytopenia.

Gestational thrombocytopenia does not usually cause symptoms unless the platelet count is very low or the drop in platelet count results from an underlying condition. It is the second most common blood-related abnormality in pregnancy, after anemia.

Share on Pinterest
Mykola Sosiukin/Getty Images

A pregnant person may find that gestational thrombocytopenia occurs in the third trimester.

Occasionally, a person with gestational thrombocytopenia may experience some mild symptoms, such as:

  • easy bruising
  • bleeding gums from brushing teeth
  • red/purple spots on the skin

For someone who is not pregnant, the average platelet count is between 150,000 and 450,000 platelets per microliter of blood. If a person’s platelet count drops too low during pregnancy, a doctor may want to monitor the person to ensure that complications do not occur.

Most instances of platelet counts lower than 150,000 during pregnancy are due to natural changes in the body. This is gestational thrombocytopenia.

However, in some cases, a low platelet count during pregnancy can indicate a disorder such as preeclampsia or HELLP syndrome. These conditions can be dangerous for both the pregnant person and the developing fetus.

Symptoms of preeclampsia include:

  • swelling and bloating, especially around the face and hands
  • high blood pressure
  • severe headaches
  • fast weight gain
  • protein in the urine
  • changes to vision
  • upper abdominal pain
  • shortness of breath

If a person has any concerns about these symptoms or anything else they experience during pregnancy, they should consult a healthcare professional.

HELLP syndrome may cause these additional symptoms:

  • fatigue
  • blurry vision
  • a general unwell feeling
  • nausea and vomiting
  • chest pain

If anyone experiences symptoms of HELLP syndrome, they should seek medical attention immediately.

The exact cause of gestational thrombocytopenia is unclear. However, some experts speculate that hemodilution and a fast rate of platelet clearance are likely causes.

Hemodilution occurs during pregnancy. Plasma is a liquid component of blood, and during hemodilution, plasma levels in the blood increase, effectively diluting the red blood cells. This means there are fewer platelets in the same volume of blood than before pregnancy.

It is also possible for platelet destruction — a normal body process — to occur at a faster-than-usual rate during pregnancy. This can occur when the spleen, which filters blood, increases in size, destroying more platelets in the process.

There are other possible causes of a low platelet count during pregnancy, such as platelets pooling in the placenta. However, many possible reasons for gestational thrombocytopenia are anecdotal, and health experts do not yet fully understand them.

Generally, gestational thrombocytopenia has no risks, as it involves a natural decrease in platelet count mainly due to benign factors.

However, a significant drop in platelet count during pregnancy may sometimes indicate an underlying condition. In these cases, depending on the condition causing it, thrombocytopenia may have some risks.

For example, if a low platelet count accompanies high blood pressure, doctors may suspect preeclampsia or HELLP syndrome as the underlying cause, and either condition may pose a risk to both the pregnant person and the fetus. Generally, both conditions have certain risks. Preeclampsia can lead to the following complications:

  • preterm delivery, or birth before 37 weeks’ gestation
  • placental abruption, or separation of the placenta from the uterus
  • seizures, in severe cases
  • organ failure

A doctor may typically diagnose gestational thrombocytopenia when a pregnant person undergoes routine tests as part of prenatal screening. Specifically, a complete blood count, which measures all the components of the blood, can indicate that a person has this condition.

If doctors detect a low platelet count in a pregnant person, they must rule out other causes. This may involve taking a history of the person’s health, doing a physical examination, and ordering further tests.

If a doctor cannot find any other reason for the low platelet count, they will diagnose gestational thrombocytopenia. This is known as a diagnosis of exclusion. The doctor will continue to monitor the person’s platelet count during standard checkups throughout the pregnancy.

Gestational thrombocytopenia does not typically pose a threat to the pregnant person or the fetus or indicate that there will be problems during delivery. This means the condition does not usually require treatment or intervention. But this applies only when there is no underlying cause.

Doctors may recommend that a person with gestational thrombocytopenia have platelet count checks every 4 weeks. If the platelet count drops significantly between these checks, doctors may increase the frequency of checks to every 2 weeks.

The condition does not pose any risk to delivery and should not increase the chance of cesarean delivery.

If a person’s platelet count is very low, a healthcare professional may avoid using medical instruments to assist with delivery. This is to avoid causing a hematoma — collection of blood outside the vessels — in the pregnant person or the baby.

Below are some commonly asked questions on the topic.

Does gestational thrombocytopenia affect the baby?

No. Gestational thrombocytopenia is unlikely to affect the baby, and in most cases, the pregnant person does not experience symptoms.

Does gestational thrombocytopenia make a pregnancy high risk?

Generally, gestational thrombocytopenia poses few to no risks. However, that is not the case if an underlying condition such as preeclampsia is responsible for the low platelet count.

If a doctor does not detect an underlying cause, they may monitor the person’s platelet count throughout the pregnancy to ensure that it does not drop low enough to present a risk.

Is gestational thrombocytopenia common?

Gestational thrombocytopenia is fairly common.

Low platelet count occurs in 5–10% of pregnancies, and 75% of these cases are due to gestational thrombocytopenia rather than a separate underlying cause.

Pregnant people may experience gestational thrombocytopenia, which is a drop in platelet count. This may be due to normal physical changes that occur in pregnancy.

Gestational thrombocytopenia does not usually cause symptoms unless the platelet count is very low or the drop results from an underlying condition. Healthcare professionals are likely to monitor a person’s platelet count throughout the pregnancy. Treatment may not always be necessary, as gestational thrombocytopenia usually resolves shortly after the pregnancy ends.

Other conditions that can occur during pregnancy may also cause a low platelet count. Before confirming a diagnosis of gestational thrombocytopenia, healthcare professionals will rule out any underlying causes for thrombocytopenia that may pose a threat to the pregnant person or the fetus.