Neutropenia in Pregnancy

Neutropenia in pregnancy is an absolute neutrophil count below 1.5 x 10^9/L (the normal range is lower in many African women, with benign ethnic neutropenia). Normal pregnancy raises neutrophil counts, so a low count needs a cause. Common causes are benign ethnic neutropenia, HIV, drugs, infection and nutritional deficiency.

• Severity: mild 1.0 to 1.5, moderate 0.5 to 1.0, severe below 0.5 x 10^9/L.
• Benign ethnic neutropenia carries no extra risk of infection.
• Severe neutropenia with fever is an emergency.

Most women have no symptoms. Severe neutropenia causes fever, mouth ulcers, sore throat, skin infection and rapid sepsis. Check temperature, mouth, throat, skin, perineum, nodes and spleen.

• Fever above 38 degrees Celsius may be the only sign of infection.
• Splenomegaly suggests hypersplenism or haematological disease.
• Differential diagnosis: benign ethnic neutropenia, HIV related neutropenia, drug induced neutropenia (zidovudine, carbimazole, co-trimoxazole), viral infection, malaria, vitamin B12 or folate deficiency, autoimmune neutropenia, hypersplenism, marrow failure or leukaemia.
• Complications: severe bacterial infection, sepsis, mouth ulceration, preterm birth, neonatal neutropenia from maternal antibodies.

The approach is a repeat count with a film and a search for treatable causes.

• Full blood count with differential and film; repeat in 2 to 4 weeks; compare with the woman's counts before pregnancy.
• HIV test and viral load, malaria test, vitamin B12, folate, ferritin, liver enzymes, antinuclear antibody, hepatitis B and C tests.
• Medication review: zidovudine, carbimazole, propylthiouracil, sulfonamides, chloramphenicol, antipsychotics.
• Bone marrow examination for severe or persistent neutropenia with other cytopenias.

The principle is to find and remove the cause, and to treat fever with neutropenia as an emergency.

• Supportive: hand hygiene; avoid contact with sick people; prompt review for fever; mouth care with chlorhexidine 0.2 percent rinse twice daily during severe neutropenia.
• Pharmacological: benign ethnic neutropenia needs no treatment; stop the offending drug and change zidovudine to tenofovir 300 mg, lamivudine 300 mg and dolutegravir 50 mg oral daily; folic acid 5 mg oral daily and cyanocobalamin 1000 micrograms IM daily for 7 days then weekly for 4 weeks if deficient; for fever above 38 degrees Celsius with neutrophils below 1.0 x 10^9/L give ceftazidime 2 g IV 8-hourly plus gentamicin 5 mg/kg IV daily within 1 hour, and add metronidazole 500 mg IV 8-hourly for abdominal or perineal sepsis; filgrastim 5 micrograms/kg subcutaneous daily for severe neutropenia with sepsis until neutrophils exceed 1.0 x 10^9/L.
• Procedures: none; marrow biopsy by a haematologist if the cause is unclear.
• Special groups: women taking co-trimoxazole prophylaxis 960 mg oral daily have weekly counts; renal impairment replaces gentamicin with ceftriaxone 2 g IV daily; babies of women with autoimmune neutropenia have a count at birth.
• Red flags: temperature above 38 degrees Celsius, neutrophils below 0.5 x 10^9/L, rigors, hypotension, mouth ulcers, perineal pain.
• Follow-up: count every 2 to 4 weeks; weekly if on a causal drug; repeat count at 6 weeks postpartum.