Gestational Thrombocytopenia: What Should You Know About Low Blood Platelets?

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Gestational thrombocytopenia is a complication of pregnancy where your platelet count is low. Platelets are cells that clot blood and help slow bleeding. When there is damage to a blood vessel in your body, platelets bind together at the site to clot blood.

Thrombocytopenia means a low platelet count in the blood. Low platelets during pregnancy are fairly common. There are several potential causes, but by far the most common cause is a benign condition called gestational thrombocytopenia.

When your platelet count dips low enough to be considered thrombocytopenia, your obstetrician will carefully monitor your blood values and take extra precautions as needed. Fortunately, gestational thrombocytopenia is usually mild and often resolves on its own after birth. 

Pregnant woman holding her stomach in hospital

Jose Luis Pelaez Inc / Getty Images

Thrombocytopenia Symptoms

Many pregnant women with thrombocytopenia experience no symptoms.

If the following symptoms occur during pregnancy, your low platelets may be caused by something else:

  • Bleeding from the gums (such as during flossing or teeth brushing)
  • Blood in the urine or stool 
  • Easy bruising
  • Fatigue 
  • Nosebleeds 
  • Petechiae (tiny red spots that indicate bleeding under the skin)

When To See Your Doctor

If you develop any new symptoms that worry you during your pregnancy, see your doctor. Uncontrolled bleeding is an emergency and requires immediate treatment. 

Thrombocytopenia During Pregnancy 

Many women experience a decreased platelet count during their pregnancies because of the changes taking place in the body. Throughout pregnancy, the number of platelets in the blood naturally decreases.

It’s estimated that gestational thrombocytopenia occurs in 7% to 12% of pregnancies in the United States. Following anemia, gestational thrombocytopenia is the second-most common hematologic abnormality during pregnancy. 

In people with gestational thrombocytopenia, the platelet count always returns to normal within a few weeks of delivery.

What Is a Normal Platelet Count?

A normal platelet count ranges from 150,000 to 450,000 platelets per microliter of blood. When your platelet count is below 150,000 platelets, you are considered to have thrombocytopenia.

A 2018 study monitored the platelet counts of pregnant women aged 15 to 44 and compared them to nonpregnant women of the same ages. Researchers found that the platelet counts of the pregnant participants naturally declined as the pregnancy progressed.

The average platelet count in the first trimester was 251,000 platelets per microliter of blood compared to 273,000 platelets in women who were not pregnant. The level continued to decline with the average platelet count at birth being 217,000 platelets.

Of the 4,568 pregnant participants in the study, 10% were diagnosed with gestational thrombocytopenia and had platelet counts of less than 150,000 platelets at birth. Women who experienced gestational thrombocytopenia were more likely to experience it again during subsequent pregnancies. 

The Pregnancy-Platelet Connection

During pregnancy, your body makes more blood plasma. This results in increased blood volume and causes hemodilution. That means you have the same number of platelet cells in a larger volume of blood. As a result, your platelet count per microliter of blood goes down. 

In addition to the natural hemodilution process, your platelet count may also decrease because they are being destroyed. During pregnancy, your spleen increases in size due to the increased blood volume. When the enlarged spleen filters your blood, it may destroy platelet cells at a higher rate. 

Rarely, a severe lack of folic acid in your diet can also lead to thrombocytopenia. This is usually not an issue for women in the United States because of prenatal vitamins.

Gestational thrombocytopenia is considered to be simply a modest exaggeration of the normal drop in blood platelets that commonly occurs in pregnancy. It does not produce bleeding problems, and is generally not associated with a higher risk of pregnancy complications. 

Diagnosis 

No one test can diagnose gestational thrombocytopenia, so your doctor will work with you to rule out other causes of low platelets before diagnosing you.

It’s estimated that 70% to 80% of cases of thrombocytopenia during pregnancy are caused by gestational thrombocytopenia.

If your platelet count falls below 100,000 platelets per microliter of blood, your doctor will likely perform additional tests, as this level is an indication that there is another cause for your thrombocytopenia. If your platelet level is below 40,000 to 50,000 platelets, then a diagnosis of gestational thrombocytopenia is very unlikely. 

Thrombocytopenia is usually considered pregnancy-specific when you have never experienced low platelets in the past (other than during previous pregnancies) and the baby is not affected. Gestational thrombocytopenia usually begins mid-pregnancy and worsens as the pregnancy progresses. It then resolves on its own within one to two months of giving birth. 

The second most common cause of thrombocytopenia during pregnancy, immune thrombocytopenia (ITP), can occur at any time and affects about 3% of pregnant people. Once the platelet count falls below 100,000 platelets, ITP is more likely to be the cause. 

Other Possible Causes of Thrombocytopenia

  • Alcohol abuse 
  • Anemia
  • Bacterial infection 
  • Cancer 
  • Chemotherapy
  • Medications 
  • Viral infection
  • Immune thrombocytopenia
  • Hemolytic uremic syndrome 
  • Preeclampsia
  • Thrombotic thrombocytopenic purpura

Precautions

Once your doctor has diagnosed you with gestational thrombocytopenia, the two of you will discuss which precautions, if any, need to be taken during the rest of your pregnancy and postpartum period. 

Monitoring and Treatment 

To monitor your platelet level, your doctor will order a complete blood count (CBC) blood test, which measures your platelet count. The frequency of tests will depend on your platelet level and symptoms you are experiencing.

With gestational thrombocytopenia, bleeding problems rarely, if ever, occur. However, measuring your platelet count at the time of labor and delivery is important because if platelets drop below 100,000, another cause of the low platelet count may be present. In that case, such extra precautions may be necessary to prevent bleeding.

Preeclampsia 

It is possible for thrombocytopenia during pregnancy to be caused by preeclampsia. Preeclampsia involves high blood pressure and signs of organ damage during pregnancy. It usually occurs after the 20th week. Preeclampsia can cause a low platelet count and accounts for about 21% of cases of thrombocytopenia at the time of birth. 

Rarely, preeclampsia can occur after childbirth as well. It often has no symptoms at all, but you may notice sudden weight gain or swelling in the hands and feet. Preeclampsia usually resolves on its own after childbirth, but needs to be monitored closely.

Frequently Asked Questions

Is it possible to prevent gestational thrombocytopenia? 

No, gestational thrombocytopenia is simply an exaggeration of the normal drop in platelets that occurs with pregnancy. Women who have gestational thrombocytopenia with one pregnancy are more likely to have it with subsequent pregnancies, but the condition is also benign with these subsequent pregnancies.

What causes gestational thrombocytopenia?

Gestational thrombocytopenia is caused by the natural changes occurring in your body during pregnancy. When you are expecting, your body increases its blood volume, causing hemodilution. This occurs when the blood plasma increases while the number of platelets remains the same. This leads to a lower platelet count per microliter of blood.

In addition to hemodilution, an increased blood volume causes the spleen to become enlarged. When this happens, the enlarged spleen traps and destroys more platelet cells during the filtering process. 

How is gestational thrombocytopenia treated?

There is no specific treatment for gestational thrombocytopenia, and none is required because it does not produce bleeding problems or any other problems with labor, delivery, or with the baby.

Can gestational thrombocytopenia affect the baby?

No, gestational thrombocytopenia does not pose a risk to you or your baby.

Summary

Gestational thrombocytopenia is usually a natural part of pregnancy. Your doctor will monitor your platelets throughout your pregnancy, and recommend any needed treatments. If your platelet count falls below 80,000 per microliter of blood, your thrombocytopenia may be caused by something else.

A Word From Verywell 

Pregnancy is a time of rapid change and can be filled with uncertainty. If you have noticed symptoms of thrombocytopenia such as bleeding gums or frequent bruising, talk with your doctor. Being diagnosed with gestational thrombocytopenia can be scary, but keep in mind that most women experience lower platelet counts temporarily toward the end of their pregnancies. It’s helpful to remember that gestational thrombocytopenia is usually mild and resolves on its own after giving birth.

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