Influenza

Pregnant individuals are particularly vulnerable to the impacts of infections such as influenza. While most will experience mild symptoms, they are at risk of heightened symptoms and sequelae particularly during the second and third trimesters. Risks include an increased likelihood of preterm birth, low birth weight or teratogenic effects if a pregnant person becomes febrile during the first trimester.

Prevention

As disease patterns shift each year, provincial and federal bodies monitor disease activity to shape their public health response. Guidance from the National Advisory Committee on Immunization (NACI) is updated regularly to provide recommendations in anticipation of the respiratory illness season. Public Health Ontario (PHO) provides province-specific information and resources, including community surveillance of disease.

During flu season, midwives can emphasize precautionary measures with clients and their support people, such as hand hygiene, masking, avoiding contact with people who are ill and vaccination.

If your midwifery practice settings does not administer the influenza vaccine, clients, including the uninsured, can attend a vaccination clinic, a doctor’s office or a pharmacy in their community. 

Management

Midwives can stay current by reviewing regular updates to recommendations from bodies such as the NACI, the Association of Medical Microbiology and Infectious Disease Canada (AMMI) and the SOGC to advise clients about their options. The Government of Canada regularly updates its respiratory virus dashboard. 

Citizen science

• People with milder symptoms may not seek formal assessment by their care providers and this data can be lost in disease surveillance.
• People can volunteer with the FluWatchers program. By joining, volunteers complete a weekly survey with questions to monitor symptoms or illness that are shared with public health. 
• Participation can help public health programs learn more about undiagnosed illness, mild flu, and healthy individuals in the community.

Research

Evidence reviewed by AMMI includes the following findings relevant to pregnant and recently postpartum individuals:

• Hospitalization and death occur at higher rates compared to non-pregnant populations with influenza.

• Increased rates of stillbirth, premature birth and infant mortality occur among pregnant people who have influenza in the third trimester.

• Oseltamivir in standard doses is recommended for the treatment of influenza during pregnancy and up to 4 weeks postpartum.

• Oseltamivir is excreted in human milk at low concentrations. Receiving this medication is not a contraindication to chest/breastfeeding due to low likelihood of clinical impact on nursing infants.

• Benefits of antiviral treatment are much greater with initiation at less than 12 hours from symptom onset than with initiation at 48 hours. However, antiviral therapy should be initiated even if the interval between illness onset and administration of antiviral medication exceeds 48 hours if the individual belongs to a group at high risk for severe disease (e.g., pregnant individuals). 

Additional resources