What is the recommended treatment for a 23-week pregnant woman presenting with influenza-like illness symptoms, including cough, body aches, fever, and decreased appetite, with normal white blood cell count (WBC) but elevated C-reactive protein (CRP)?

Treatment Recommendation for Pregnant Woman with Influenza-Like Illness at 23 Weeks

Start oseltamivir 75 mg orally twice daily for 5 days immediately, without waiting for laboratory confirmation of influenza. 1, 2, 3, 4

Immediate Antiviral Treatment

• Oseltamivir is the first-line treatment for all pregnant women with suspected or confirmed influenza, regardless of trimester, vaccination status, or timing of symptom onset. 1, 2, 4

• The standard adult dosing is 75 mg orally twice daily for 5 days. 5, 1, 3

• Treatment should begin immediately based on clinical presentation (fever, cough, body aches, decreased appetite) without waiting for laboratory confirmation. 2, 4

• While ideally started within 48 hours of symptom onset, treatment should not be withheld even if this window has passed—this patient is at day 3 of symptoms and should still receive treatment. 5, 2, 4

• Taking oseltamivir with food significantly reduces the most common side effect (nausea, occurring in ~10% of patients). 1, 2, 3

Clinical Rationale for Aggressive Treatment

Pregnancy itself is a high-risk condition for influenza complications, with risk escalating as gestation advances:

• Pregnant women face higher risk for severe illness, pneumonia, ICU admission, and death compared to non-pregnant women. 1, 2

• The relative risk for hospitalization increases from 1.4 at weeks 14-20 to 4.7 at weeks 37-42 of gestation. 1, 2

• At 23 weeks, this patient is entering the period of progressively increasing risk. 5

• Influenza infection during pregnancy is associated with increased odds of congenital anomalies, stillbirth, late pregnancy loss, preterm delivery, low birth weight, and small-for-gestational-age infants. 1, 2

Safety Profile in Pregnancy

Oseltamivir has extensive safety data supporting its use throughout pregnancy:

• No adverse effects have been reported among women who received oseltamivir during pregnancy or among their infants in post-marketing surveillance. 2, 3

• A 5-year retrospective cohort of over 10,000 women found no association between first-trimester oseltamivir exposure and major congenital malformations. 1

• A systematic review and meta-analysis of 15 studies showed no association between congenital defects and influenza treatment in any trimester. 1

• In a prospective cohort study of 716 pregnancies, first-trimester oseltamivir exposure resulted in 6.7% major birth defects compared to 7.9% in unexposed pregnancies (RR 0.84,95% CI 0.19-2.80). 6

• The FDA classifies oseltamivir as Pregnancy Category C, but extensive observational data demonstrate reassuring safety outcomes. 2

Interpretation of Laboratory Findings

• Normal WBC does not rule out influenza—viral infections typically do not cause leukocytosis. 5

• Elevated CRP (48 mg/L) indicates an inflammatory response consistent with viral infection and supports the clinical diagnosis of influenza-like illness. 5

• These laboratory findings, combined with the clinical presentation during influenza season, warrant empiric treatment. 5, 4

Alternative Treatment Option

• Zanamivir 10 mg (two 5 mg inhalations) twice daily for 5 days can be used if oseltamivir is contraindicated or unavailable, though oseltamivir remains preferred. 5, 1, 2

• Zanamivir has limited systemic absorption but carries potential respiratory complications, particularly in women with underlying respiratory conditions. 2

Symptomatic Management

• Acetaminophen should be used concurrently for fever management, as fever itself poses risks to fetal development. 2

• Ensure adequate hydration and rest. 1

• The hoarse cough can be managed with supportive care; antibiotics are not routinely required for uncomplicated influenza without evidence of bacterial superinfection. 5

Warning Signs Requiring Urgent Evaluation

Instruct the patient to seek immediate care if she develops:

• Difficulty breathing or chest pain 1, 2
• Persistent high fever despite treatment 1, 2
• Decreased fetal movement 1, 2
• Signs of preterm labor (regular contractions, pelvic pressure, vaginal bleeding or fluid) 1, 2

Common Pitfalls to Avoid

• Do not delay treatment waiting for influenza testing—clinical diagnosis is sufficient, and test results may take days. 2, 4

• Do not withhold treatment because symptoms started >48 hours ago—pregnant women benefit from treatment even when started later. 2, 4

• Do not prescribe antibiotics empirically unless there is evidence of bacterial superinfection (this patient has normal WBC and no focal findings suggesting pneumonia). 5

• Do not reduce the dose—pregnant women receive the same adult dosing as non-pregnant adults. 5, 1, 3

Prevention for Future Pregnancies

• All pregnant women should receive inactivated influenza vaccine (IIV) during any trimester, including the first trimester, for future influenza seasons. 5, 1

• Vaccination is safe throughout pregnancy and protects both mother and infant, with infants born to vaccinated mothers having up to 72% risk reduction for laboratory-confirmed influenza hospitalization in the first months of life. 2