What is the management approach for leukocytosis (elevated white blood cell count) in a pregnant or postpartum patient?

Management of Leukocytosis in Pregnancy and Postpartum

Leukocytosis in pregnancy is physiologic in most cases, with the upper reference limit for total WBC increasing by 36% during pregnancy and neutrophils increasing by 55%, requiring no intervention unless accompanied by symptoms or exceeds 20 × 10⁹/L. 1

Initial Diagnostic Approach

Determine if the leukocytosis is physiologic or pathologic:

• Physiologic leukocytosis occurs commonly throughout pregnancy, particularly in the third trimester, and resolves spontaneously after delivery 2, 3
• Pathologic leukocytosis (WBC >20 × 10⁹/L) persisting for weeks or accompanied by constitutional symptoms (fever, weight loss, bruising, fatigue) requires immediate investigation 1, 2, 3

Evaluation Algorithm

Step 1: Assess for Infection

• If urinary symptoms present: Obtain urine culture before initiating antibiotics using clean-catch midstream or catheterized specimen 1
• Pyuria plus bacteriuria plus symptoms indicates true UTI requiring treatment 1
• Initiate empirical antibiotics while awaiting culture if symptomatic to prevent maternal and fetal complications 1
• Note: Negative nitrites do not exclude UTI (only 53% sensitivity) 1
• Activated neutrophils on peripheral smear suggest infectious etiology 4

Step 2: Examine Peripheral Blood Smear

• Pleomorphic lymphocytes suggest reactive process 4
• Monomorphic lymphocyte population favors lymphoproliferative disorder requiring flow cytometry 4
• Blasts or blast equivalents, immature granulocytes, basophils, or dysplasia indicate myeloid malignancy requiring bone marrow examination 4

Step 3: Rule Out Hematologic Malignancy

Constitutional symptoms (fever, weight loss, bruising, fatigue) plus abnormal peripheral smear mandate urgent hematology referral. 5, 3

Management of Malignant Leukocytosis

Acute Myeloid Leukemia (AML)

Treatment must begin immediately without delay regardless of trimester, as any delay compromises maternal survival. 1

• First step: Discuss therapeutic termination once patient is hemodynamically stable, allowing immediate standard therapy 1

• If pregnancy continuation desired:

  • Use daunorubicin monotherapy (NOT idarubicin) at 60 mg/m² days 1-3 plus cytarabine 100-200 mg/m² days 1-7 1
  • Idarubicin is absolutely contraindicated due to higher lipophilicity causing increased placental transfer and fetal toxicity 1
  • ATRA is contraindicated in first trimester due to high teratogenicity 1

• For acute promyelocytic leukemia: Doxorubicin plus ATRA can be used starting in second trimester 1

• In third trimester: Consider inducing labor and initiating therapy after delivery 1

• Never delay treatment to reach a "safer" gestational age—maternal mortality increases with delays 1

Chronic Myeloid Leukemia (CML)

• First trimester: Interferon-alpha is safe and preferred 1
• Second and third trimesters: Interferon-alpha OR imatinib can be used 1

Lymphoma

• Non-Hodgkin lymphoma requiring treatment: CHOP chemotherapy starting in second trimester shows favorable pregnancy outcomes 1
• Hodgkin lymphoma: ABVD chemotherapy starting in second trimester without significant fetal impairment 1

Management of Benign Leukocytosis

Pregnancy-Induced Leukocytosis

• Asymptomatic leukocytosis requires no treatment—avoid unnecessary antibiotics as this may cause more harm than benefit 1
• Monitor WBC counts through third trimester 2
• Expect spontaneous resolution within 24 hours after delivery 2, 6

Refractory Cases

For severe, symptomatic leukocytosis (>20 × 10⁹/L) persisting despite evaluation and treatment, termination of pregnancy may be the most effective treatment approach. 2, 6

• Case reports demonstrate normalization of WBC within 24 hours post-cesarean section 2, 6
• This appears related to pregnancy-induced immunoregulation that resolves with delivery 2, 6

Special Considerations

Multidisciplinary Management

• Mandatory team involvement for malignant causes: hematologist, obstetrician, and neonatologist must collaborate from diagnosis 1
• High-risk obstetrics consultation for myeloproliferative neoplasms 7

Delivery Planning

• For deliveries before 36 weeks: Administer antenatal corticosteroids to reduce respiratory distress syndrome risk 1
• Platelet count ≥50 × 10⁹/L is adequate for cesarean section 7
• Platelet count ≥75 × 10⁹/L generally recommended for spinal or epidural anesthesia 7

Postpartum Considerations

• Breastfeeding is contraindicated if chemotherapy or arsenic trioxide continues after delivery 1
• Never use arsenic trioxide at any trimester due to severe embryotoxicity 1