What is the recommended management for a pregnant woman in her first trimester with cough and influenza?

Management of Cough and Influenza in First Trimester Pregnancy

Pregnant women with suspected or confirmed influenza in the first trimester should receive immediate antiviral treatment with oseltamivir 75 mg twice daily for 5 days, regardless of vaccination status or time since symptom onset. 1

Immediate Antiviral Treatment

Start oseltamivir presumptively based on clinical symptoms alone—do not wait for laboratory confirmation or delay treatment beyond 48 hours. 1, 2

• Oseltamivir dosing: 75 mg orally twice daily for 5 days 3
• Treatment should begin immediately upon suspicion of influenza, even if more than 48 hours have passed since symptom onset 1, 2
• Laboratory testing is not required before initiating treatment 1, 2
• Over-the-phone prescribing is preferred for low-risk patients to reduce disease transmission in the office 1

Alternative option: Zanamivir 10 mg (two 5 mg inhalations) twice daily for 5 days can be used if oseltamivir is contraindicated 3

Safety Profile in First Trimester

The evidence strongly supports the safety of both influenza vaccination and antiviral treatment during the first trimester:

• Vaccination safety: Multiple large studies including a 5-year retrospective cohort of over 10,000 women found no association between first trimester influenza vaccination and major congenital malformations 3
• A systematic review and meta-analysis of 15 studies (14 cohort studies and 1 case-control study) showed no association between congenital defects and influenza vaccination in any trimester, including the first 3
• Oseltamivir safety: Available data from published studies suggest that oseltamivir use during pregnancy is not associated with increased risk of birth defects or adverse maternal or fetal outcomes 4
• Most common side effects of oseltamivir are nausea (10%) and vomiting (9%), which are generally well-tolerated 5

Clinical Rationale for Aggressive Treatment

Pregnant women face substantially elevated risks from influenza infection:

• Increased maternal morbidity: Pregnant women are at higher risk for severe illness, pneumonia, ICU admission, and death compared to non-pregnant women 3, 1, 2
• Increased hospitalization risk: The relative risk for hospitalization increases from 1.4 during weeks 14-20 of gestation to 4.7 during weeks 37-42 3
• Fetal risks: 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 3, 2, 6
• First trimester vulnerability: Evidence suggests the risk of fetal death and adverse birth outcomes is greatest for women infected during their first trimester 3

Vaccination Recommendations

All pregnant women should receive inactivated influenza vaccine (IIV) during any trimester, including the first trimester. 3, 7

• Any licensed, recommended, age-appropriate inactivated influenza vaccine (IIV3 or IIV4) or recombinant influenza vaccine (RIV3 or RIV4) may be used 3
• Live attenuated influenza vaccine (LAIV) is contraindicated during pregnancy 3
• Vaccination can be administered at any time during pregnancy and does not need to wait until after the first trimester 3, 7
• Vaccination protects both the mother and provides passive immunity to the infant for the first 6 months of life, with up to 72% risk reduction for laboratory-confirmed influenza hospitalization in infants 3, 5

Post-Exposure Prophylaxis

Consider oseltamivir prophylaxis (75 mg once daily for 10 days) for pregnant women who have had close contact with confirmed influenza cases, particularly if unvaccinated. 1

• The CDC advises that postexposure chemoprophylaxis can be considered for pregnant women who have had close contact with infectious individuals 1
• Prophylaxis is especially important for unvaccinated women or those with high-risk medical conditions 1

Common Pitfalls to Avoid

• Do not delay treatment waiting for laboratory confirmation—clinical diagnosis is sufficient 1, 2
• Do not withhold treatment if beyond 48 hours of symptom onset—oseltamivir still provides benefit when started later 1, 2
• Do not avoid vaccination or treatment in the first trimester due to safety concerns—the risks of untreated influenza far outweigh any theoretical medication risks 3, 1, 2
• Do not use baloxavir marboxil during pregnancy—data on its use during pregnancy is limited and the CDC does not recommend it for pregnant women 3, 5

Symptomatic Management of Cough

While treating the underlying influenza infection with antivirals:

• Acetaminophen is safe for fever and discomfort during pregnancy 8
• Adequate hydration and rest are essential supportive measures
• Monitor for warning signs requiring urgent evaluation: difficulty breathing, chest pain, persistent high fever, decreased fetal movement, or signs of preterm labor