Your Pregnancy Matters
How can having low platelets affect my pregnancy and birth plan?
March 16, 2021
In February, a very pregnant Mandy Moore, star of the popular TV series "This Is Us," revealed that she had to alter her birth plan due to a diagnosis of low blood platelets. Though Moore didn't elaborate on what specifically changed, low platelets (thrombocytopenia) is a fairly common condition.
Platelets, also called thrombocytes, are the smallest human blood cells and play a crucial role in blood clotting. Released by your bone marrow, the quantity of these specialized cells in your blood is generally reported on a complete blood count (CBC).
Pregnancy is generally a “pro-clotting” state, which makes sense – clotting helps protect women from excessive bleeding at delivery. But there is a delicate balance between activities that help your blood clot and those that cause too much clotting.
At their best, platelets combine with other factors in the blood that control bleeding and help plug holes in the walls of blood vessels.
At their worst, platelets can form clots in the blood vessels in areas that have plaque buildup. This can put you at increased risk for heart attacks and strokes. When you have too few platelets, called thrombocytopenia, maternal complications such as excessive bleeding, premature delivery, or inability to get an epidural can arise.
Thrombocytopenia is often a "silent" condition, causing few noticeable symptoms. Patients have reported mild symptoms such as bleeding gums while brushing their teeth, easy bruising, or reddish-purple spots (petechiae) caused by bleeding below the skin.
However, thrombocytopenia can turn serious quickly. Patients with low platelets need to understand their personal risk during pregnancy and delivery, starting with the root cause of their condition.
What causes low platelets in pregnancy?
Outside of pregnancy, a normal platelet count ranges from 150,000 to 450,000/µL (platelets per microliter of blood).
It's normal for your platelet count to dip by a few thousand during pregnancy, due in part to hemodilution: the body makes more plasma during pregnancy, so the total number of platelets per volume of blood will be lower.
When the number dips below 100,000-150,000/µL, your doctor will want to keep a closer eye on you to reduce the risk of complications.
During pregnancy, about 10 percent of women have platelets counts below 150,000/µL. Of these, approximately:
- 75 percent are due to normal changes in pregnancy
- 21 percent are related to hypertensive diseases, such as preeclampsia or HELLP syndrome
- 4 percent are due to inherited or immunological conditions in which the immune system makes antibodies which attack platelet cells
Approximately 1 percent of patients have platelets counts of less than 100,000/µL, which might impact pregnancy management.
Platelets may be destroyed at a higher rate in pregnancy. As the spleen increases in size due to increased blood volume during pregnancy, it may destroy more platelets in the filtering process.
A severe lack of folic acid in your blood can cause thrombocytopenia, so it is important to take your prenatal vitamins. Certain bacterial and viral illnesses such as Epstein-Barr, HIV, and hepatitis B and C can also lower your platelet count.
Chemotherapy and radiation therapy can decrease the body's platelet production. Medications such as heparin, anticonvulsants, and antibiotics that contain sulfamethoxazole – common in medications for ear, urine, and respiratory infections – can also decrease production.
Risks for mom and baby
Low platelet counts can lead to:
- Inability to have an epidural during labor due to a risk of epidural hematoma, in which abnormal blood collection in the spine can cause spinal cord damage.
- Increased bleeding at the time of vaginal or cesarean section delivery.
- Premature delivery if the reduction in platelets is due to severe preeclampsia.
The baby is unlikely to develop low platelets if your decreased count is caused by regular dips in pregnancy or hypertension. However, if your low count is due to an immune condition, the antibodies that destroy platelets may cross the placenta and cause the same issues for the fetus.
Most patients with low platelets do not require treatment – just observation. Your doctor may recommend taking folate and vitamin B12 supplements to support platelet production.
Certain foods can also help increase your platelet levels, including:
- Dark chocolate
- Dark, leafy green vegetables, such as spinach and kale
- Lean beef and beef liver
- Black-eyed peas and lentils
- Fortified breakfast cereals
- Fortified dairy alternatives
- Produce rich in vitamin C, such as oranges, Brussels sprouts, and red peppers
While fatty fish such as salmon are high in Vitamin B12 and can also boost platelet production, pregnant women are advised to sparingly eat seafood that is high in mercury.
Patients with hypertensive disorders need closer monitoring and may have to deliver early to reduce their risk of cardiovascular damage. After delivery, the platelet count generally springs back to normal within a few days.
Immune conditions that can cause low platelets, such as immune thrombocytopenia purpura (ITP), may require steroids or IV immunoglobulin (antibody) treatment. Giving you antibodies may help prevent your immune system from attacking your healthy platelets. In rare and severe cases, your doctor may recommend removing your spleen during pregnancy.
Ask questions about your lab results
It can be alarming to see a word like "thrombocytopenia" or a low number compared with the baseline on your lab results.
For most patients, having mild-to-moderate low platelets won't change your pregnancy care or birth plan much, if at all. Moore, despite the changes to her plan, announced on Instagram that her healthy baby boy arrived on his due date in late February.
However, it is important to talk with your doctor about your risks for complications related to low platelets. If your lab results indicate low platelets, follow Moore's lead – ask your provider to explain what that means for you. We're hear to help you make informed decisions and have a healthier, safer pregnancy and delivery.