Influenza
Pregnant individuals are no more likely to contract viruses than the general population, but they are particularly vulnerable to their effects, especially those like the H1N1 (swine influenza) virus. While most pregnant individuals with influenza experience mild symptoms, they are at risk of heightened symptoms and sequelae particularly during the second and third trimesters. Some studies also suggest that their fetuses are at increased risk of preterm birth or low birth weight or teratogenic effects as a result of maternal fever (i.e., 38 C or higher) during the first trimester.
During flu season, midwives may wish to emphasize precautionary measures with their clients, such as hand hygiene, masking, avoiding contact with people who are ill and vaccination. Some midwifery practice settings will stock the influenza vaccine; if yours does not, clients interested in vaccination can attend a vaccination clinic, a general practitioner’s office or a pharmacy.
To reduce the risk of severe illness that could arise from co-infection with COVID-19 and influenza, individuals who are at high risk of severe COVID-19 related illness or those capable of transmitting influenza to those at high risk of severe and critical illness related to COVID-19 are particularly recommended to receive the influenza vaccine this fall… Individuals at high risk of influenza-related complications or who are more likely to require hospitalization [include] all pregnant individuals.
The Public Health Agency of Canada has a number of resources and publications on influenza for both clients and health care providers including the most recent statement (2024/25) on the seasonal influenza vaccine. Public Health Ontario has a number of resources specific to the provision of care in Ontario.
Symptoms
It can be difficult to differentiate between the flu, COVID-19 and the common cold. However, both the flu and COVID-19 can be much more severe. Flu symptoms almost always include:
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A sudden onset of fever or feeling feverish
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A cough and/or sore throat
Flu symptoms commonly include:
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A runny or stuffy nose
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Headaches and/or body aches
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Chills
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Fatigue (feeling tired)
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Decreased appetite
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Nausea, vomiting, and/or diarrhea (mostly in children)
Clients should be advised to page if they develop any of these symptoms for assessment and a referral to a physician for possible prescription of antivirals.
Guidelines on the Treatment of Seasonal Influenza
The Association of Medical Microbiology and Infectious Diseases Canada (AMMI) released updated guidance on the vaccination and treatment of seasonal influenza in 2019. The AOM has not reviewed the evidence upon which its recommendations are based. The guidelines make the following conclusions of relevance to midwives:
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“During seasonal influenza epidemics, healthy pregnant women with influenza, especially those in the third trimester of pregnancy, experienced rates of hospitalization in excess of those observed in age-matched non-pregnant women with influenza. Moreover, the rates of hospitalization were comparable to those observed in individuals with other recognized comorbid conditions that increase the risk of influenza-related complications. As a result of such data, pregnancy is now recognized as a risk factor that underscores the need for annual influenza immunization.
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During the 2009 influenza A(H1N1) pandemic, not only were increased rates of hospitalization observed among healthy pregnant women, especially in the second and third trimester, but so too was an increased rate of death compared with that among non-pregnant women.
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A recent meta-analysis demonstrated that women who were less than 4 weeks post-partum were at the greatest risk of death. New evidence indicates that a significant increase in stillbirths, premature deliveries, and infant mortality occurs among women who have influenza in the third trimester. Oseltamivir is now recommended for the treatment of influenza in pregnant women.
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Oseltamivir in standard doses is recommended for treatment of women with influenza during pregnancy and up to 4 weeks post-partum on the basis of epidemiological data demonstrating an association between pregnancy and the immediate post-partum period and an increased risk of severe influenza combined with data demonstrating the extensive safe use of oseltamivir to treat such patients during the 2009 H1N1 pandemic.
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Oseltamivir is excreted in breast milk at low concentrations.
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Treatment should be initiated as rapidly as possible after onset of illness because the benefits of treatment are much greater with initiation at less than 12 hours than with initiation at 48 hours.
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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]”.
Midwives may wish to consider these treatment recommendations when advising clients about when to page. Midwives should consider whether their knowledge allows them to have informed choice discussions about treatment or whether to refer clients to physicians for information about treatment and these AMMI recommendations. Because oseltamivir is not listed in the midwifery pharmacopeia, midwives would need to consult with a physician for clients wishing treatment.
Resources
Ministry of Health and Long Term Care: Universal Influenza Immunization Program (UIIP)
Seasonal Respiratory Pathogens Guide v. 1.0, July 2024 (Ministry of Health, PDF 523 KB)
2021–2022 AMMI Canada guidance on the use of antiviral drugs for influenza in the COVID-19 pandemic setting in Canada (Association of Medical Microbiology and Infectious Diseases Canada)
Use of antiviral drugs for seasonal influenza: Foundation document for practitioners—Update 2019 (Association of Medical Microbiology and Infectious Diseases Canada)
Influenza (flu) (Public Health Ontario)