How is thrombocytopenia (low platelet count) managed in pregnancy?

Management of Thrombocytopenia in Pregnancy

The mode of delivery should be determined by obstetric indications alone, not by maternal platelet count, and treatment is indicated when platelets fall below 20,000-30,000/μL or with any bleeding symptoms. 1, 2

Diagnostic Approach

The first critical step is distinguishing immune thrombocytopenic purpura (ITP) from gestational thrombocytopenia and pregnancy-specific causes:

• Gestational thrombocytopenia accounts for approximately 75% of thrombocytopenia in pregnancy, characterized by asymptomatic mild thrombocytopenia (typically >70,000/μL), no prior history except possibly in previous pregnancy, occurrence in late gestation, and spontaneous resolution after delivery. 1

• Exclude pregnancy-specific causes including preeclampsia, HELLP syndrome, DIC, acute fatty liver, folate deficiency, massive obstetrical hemorrhage, and antiphospholipid antibody syndrome by obtaining blood pressure measurements and liver function tests. 2

• Bone marrow examination is not required to diagnose ITP in pregnancy. 2

• Antiplatelet antibody testing has no diagnostic value and should not be routinely performed. 2

• A thorough history is essential: evidence of thrombocytopenia when not pregnant strongly suggests ITP rather than gestational thrombocytopenia. 1

Treatment Thresholds

Treatment decisions are based on platelet count and bleeding symptoms, not gestational age alone:

• Platelets ≥30,000/μL in first two trimesters: No treatment required if asymptomatic. 2

• Platelets <20,000-30,000/μL: Treatment indicated even if asymptomatic. 2

• Any symptomatic bleeding: Treatment required regardless of platelet count. 2

First-Line Treatment Options

Corticosteroids

• Prednisone 10-20 mg/day is the initial treatment of choice, adjusted to the minimum dose that maintains a hemostatically effective platelet count. 1, 2

• Avoid aggressive tapering in the last weeks before delivery as thrombocytopenia may worsen. 1

• Monitor for side effects including hypertension, hyperglycemia, osteoporosis, excessive weight gain, and psychosis. 1

• After delivery, taper corticosteroids slowly while monitoring platelet count and maternal mental state. 1

Intravenous Immunoglobulin (IVIg)

• Use IVIg when corticosteroids are ineffective, significant side effects occur, or more rapid platelet increase is required. 1, 2

• Single IVIg infusions may be repeated as needed to prevent hemorrhage and provide adequate platelet count for delivery. 1

• Response rates are similar to non-pregnant patients. 1

IV Anti-D

• For non-splenectomized Rh(D)-positive patients: IV anti-D 50-75 μg/kg is effective and safe in second and third trimesters. 1

• Monitor neonates for jaundice, anemia, and direct antiglobulin test positivity after delivery. 1

• Augmentation with corticosteroids or IVIg is usually required to achieve platelet count of 50,000/μL for delivery. 1

Refractory Cases

For patients failing first-line treatment:

• Combine first-line therapies: High-dose methylprednisolone (1000 mg) possibly with IVIg or azathioprine in the weeks before delivery. 1

• Azathioprine is safe during pregnancy based on data from SLE and renal transplantation, but response is slow. 1

• Cyclosporin A has not been associated with significant maternal or fetal toxicity. 1

• Splenectomy, if necessary, is best performed in the second trimester and may be done laparoscopically, though technique becomes difficult beyond 20 weeks' gestation. 1

Management of Delivery

Critical evidence-based delivery management:

• Mode of delivery is determined by obstetric indications only, not by maternal or predicted fetal platelet count. 1, 2

• No evidence supports cesarean section as safer for the thrombocytopenic fetus compared to uncomplicated vaginal delivery. 1

• Neonatal mortality rate is less than 1% in babies born to mothers with ITP. 1

• Severe neonatal thrombocytopenia occurs in 8.9-14.7% of cases, with intracranial hemorrhage in 0-1.5% of thrombocytopenic infants. 1

• Most neonatal hemorrhagic events occur 24-48 hours after delivery at the nadir of platelet count, not during delivery itself. 1

Platelet Transfusion Thresholds for Delivery

• Prophylactic platelet transfusions are appropriate when platelets <10,000/μL with planned cesarean section or with epistaxis/mucous membrane bleeding and expected vaginal delivery. 2

Neonatal Management

Systematic neonatal monitoring is essential:

• Check neonatal platelet count for 3-4 days after birth. 2

• Consider brain imaging if platelet count at birth is <20,000/μL. 2

• IVIg is appropriate if infant's platelets <20,000/μL without evidence of intracranial hemorrhage. 2

• Fetal platelet count cannot be reliably predicted by maternal platelet count, platelet antibody levels, or history of maternal splenectomy. 1

• Fetal blood sampling by cordocentesis carries 1-2% fetal mortality risk, at least as high as the risk of intracranial hemorrhage it aims to prevent. 1

Common Pitfalls to Avoid

• Do not perform cesarean section based solely on maternal ITP diagnosis or low platelet count—this increases maternal morbidity without reducing neonatal risk. 1

• Do not use fetal scalp sampling or cordocentesis to guide delivery mode—the procedural risks exceed the benefits. 1

• Do not withhold pregnancy counseling—it is rarely necessary to advise ITP patients against pregnancy. 1

• Do not assume gestational thrombocytopenia in patients with platelets <70,000/μL or thrombocytopenia discovered early in pregnancy—these features suggest ITP. 1