Influenza in Pregnancy

Influenza in pregnancy is infection with influenza A or B virus, causing fever, cough and body aches. Pregnant women have a higher risk of pneumonia, intensive care admission and death, particularly in the second and third trimesters. It matters because early antiviral treatment lowers severity, and vaccination protects the mother and the baby after birth.

• Risk factors: pregnancy, asthma, HIV, diabetes, obesity, heart disease.
• Fever in early pregnancy may raise the risk of neural tube defects.
• Treat without waiting for test results.

Women have sudden fever, chills, headache, myalgia, dry cough, sore throat and fatigue, sometimes with vomiting. Breathlessness, chest pain or confusion suggests pneumonia.

• Fever above 38 degrees Celsius.
• Symptoms peak in 2 to 3 days.
• Differential diagnosis: COVID-19, malaria, pneumonia, other viral respiratory infection, dengue, typhoid, urinary tract infection.
• Complications: viral or bacterial pneumonia, respiratory failure, preterm labour, fetal distress, miscarriage, maternal death.

The diagnosis is clinical, confirmed by testing where available, and treatment starts before results.

• Influenza rapid antigen or PCR on nasal or throat swab.
• Oxygen saturation and respiratory rate; chest X-ray with shielding if there is chest involvement.
• Full blood count, urea, creatinine; malaria test and COVID-19 test.
• Blood culture and sputum culture for severe disease.

The principle is early oseltamivir, fever control and monitoring for pneumonia.

• Supportive: rest; oral fluids 2 to 3 litres daily; left lateral position; paracetamol to keep temperature below 38 degrees Celsius; admit if breathing is difficult or saturation is below 94 percent.
• Pharmacological: oseltamivir 75 mg oral 12-hourly for 5 days, started within 48 hours but given even later in severe disease (10 days if severely ill); paracetamol 1 g oral 6-hourly (maximum 4 g in 24 hours); for secondary bacterial pneumonia give amoxicillin-clavulanate 625 mg oral 8-hourly for 7 days, or ceftriaxone 2 g IV daily plus azithromycin 500 mg oral or IV daily for severe cases; post exposure prophylaxis with oseltamivir 75 mg oral once daily for 10 days; inactivated influenza vaccine 0.5 mL IM once each season in any trimester.
• Procedures: ventilation for respiratory failure.
• Special groups: oseltamivir dose in renal impairment (creatinine clearance 30 to 60 mL/minute) is 30 mg oral 12-hourly; breastfeeding continues with a mask and hand washing; neonates of infected mothers are monitored for fever and breathing difficulty.
• Red flags: breathlessness, oxygen saturation below 94 percent, persistent fever beyond 3 days, chest pain, confusion, reduced fetal movements.
• Follow-up: review at 48 to 72 hours; growth scan after recovery if illness was severe; vaccinate in every pregnancy.