What to Know About Low Blood Platelets in Pregnancy

Having gestational thrombocytopenia, or low platelets in pregnancy, does not cause bleeding problems and is not usually associated with a higher risk of pregnancy-related complications. Gestational thrombocytopenia is usually mild and often resolves on its own after birth. 

This drop in these cells that help the blood to clot (platelets) occurs in about 10% of pregnancies. It's normal for your platelet count to drop during pregnancy. However, if your count drops below a certain level, your obstetrician will carefully monitor your blood levels and take precautions as needed. 

This article will cover the symptoms, causes, and complications associated with low platelets in pregnancy. 

Low Platelet Symptoms in Pregnancy

Many pregnant people with thrombocytopenia experience no symptoms. If you low platelet levels and the following symptoms during your pregnancy, gestational thrombocytopenia may not be the cause:

• Bleeding from the gums (e.g., during flossing or teeth brushing)
• Blood in the urine or stool 
• Easy bruising
• Fatigue 
• Nosebleeds 
• Tiny red spots that indicate bleeding under the skin (petechiae)

Causes of Low Platelets in Pregnancy

Many people will have a decreased platelet count during their pregnancies because of the many changes happening in the body. Throughout pregnancy, the number of platelets in the blood naturally goes down.

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

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

During pregnancy, your body makes more blood plasma which leads to increased blood volume and hemodilution. Hemodilution 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 process of hemodilution, your platelet count may also go down because the cells are being destroyed. 

During pregnancy, your spleen gets bigger because of 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 pregnant people in the U.S. because they usually take prenatal vitamins that provide enough folic acid.

Gestational thrombocytopenia is considered to be just a little more than the normal drop in blood platelets that is common during pregnancy. It does not cause bleeding problems and is generally not associated with a higher risk of pregnancy complications. 

A 2018 study looked at the platelet counts of pregnant women aged 15 to 44 and compared them to nonpregnant women of the same ages. The researchers found that the platelet counts of the pregnant people naturally went down as their pregnancies progressed.

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

Of the 4,568 pregnant people in the study, 10% were diagnosed with gestational thrombocytopenia and had platelet counts of less than 150,000 platelets at birth. The researchers also noted that the women who had gestational thrombocytopenia were more likely to have it in their later pregnancies, too. 

Diagnosis 

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

If your platelet count falls below 100,000 platelets per microliter of blood, your provider will likely do additional tests, as this level means 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 had low platelets in the past (other than during previous pregnancies) and the fetus is not affected by it. Gestational thrombocytopenia usually begins mid-pregnancy and gets worse as the pregnancy goes on. It then gets better on its own within one to two months of giving birth. 

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

Precautions

Once your provider has diagnosed you with gestational thrombocytopenia, they will go over what precautions, if any, need to be taken during the rest of your pregnancy and postpartum period. 

Treatment

To monitor your platelet level, your provider will do a complete blood count (CBC) blood test, which includes a measure of your platelet count. 

How often they want to do these tests will depend on your platelet level and whether you have any symptoms. 

With gestational thrombocytopenia, bleeding problems rarely happen. However, measuring your platelet count at the time of labor and delivery is important because if your platelets drop below 100,000, it’s a sign there could be another cause of the low platelet count. In that case, extra precautions might be necessary to prevent bleeding during delivery and after you give birth. 

The treatment will depend on your platelet counts, your health, and the health of your pregnancy. You may need to get medicine through an IV in the hospital, including steroids and immunoglobulin.

Other treatment options like monoclonal antibodies and immunosuppressant drugs have also been explored. In more severe cases, you may need a transfusion or surgery to take out your spleen. 

Preeclampsia 

It is possible for thrombocytopenia during pregnancy to be caused by a serious condition that causes high blood pressure and signs of organ damage (preeclampsia). The condition usually occurs after the 20th week of pregnancy.

Preeclampsia can cause a low platelet count and is the cause of about 21% of cases of thrombocytopenia at the time of birth. Sometimes, preeclampsia can come on after you give birth. It often has no symptoms at all, but you may notice sudden weight gain or swelling in your hands and feet. 

Preeclampsia needs to be monitored closely as severe, untreated cases can lead to a seizure disorder (eclampsia) or HELLP syndrome (a multi-organ condition).

For people at high risk, daily low-dose aspirin might be recommended to help prevent preeclampsia and its complications. The treatment should be started between 12 to 28 weeks of pregnancy, preferably before 16 weeks.

Once the condition develops, the only cure is the delivery of the baby. If the condition comes on after childbirth, you will be admitted to the hospital for treatment and observation. The treatment for preeclampsia usually includes a medication called magnesium sulfate.

Summary

Gestational thrombocytopenia is usually a natural part of pregnancy. Your provider will monitor your platelet counts throughout your pregnancy, and recommend any treatment or precautions, if needed. 

Usually, the condition does not cause any serious or lasting problems for you or the fetus and gets better shortly after you give birth. 

If your platelet count falls below 80,000 per microliter of blood, it’s usually a sign that something else is causing you to have low platelets. Your provider may want to do more tests to figure out what the cause is and make sure you get the right treatment. 

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.