Influenza

Pregnant women are no more likely to contract a virus, but are particularly vulnerable to their effects, especially those like the H1N1 (swine influenza) virus. While most pregnant women with influenza experience mild symptoms, they are at risk of heightened symptoms and sequelae during the second and third trimesters. Some studies also suggest that their fetuses are also 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 also wish to discuss precautionary measures with their clients, such as hand hygiene, avoiding contact with people who are ill and vaccination. Since midwives do not currently administer influenza vaccination, clients interested in vaccination, can attend a vaccination clinic, a general practitioner’s office or a pharmacy.

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 on the seasonal influenza vaccine.  The Ontario Ministry of Health and Long-Term Care influenza page for health-care providers also has a number of resources specific to the provision of care in Ontario.

Symptoms

The flu (including H1N1) and the common cold have similar symptoms with the flu being more severe. Flu symptoms almost always include:

  • A sudden onset of fever or feeling feverish
  • A cough and/or sore throat

Flu symptoms commonly include:

  • A runny or stuffy nose
  • Headaches and/or body aches
  • Chills
  • Fatigue (feeling tired)
  • Decreased appetite
  • Nausea, vomiting, and/or diarrhea (mostly in children).

Where clients present with these symptoms, midwives should consider referring them to a physician for possible prescription of antivirals. In 2014, the Ministry of Health and Long-Term Care noted that:

Because the risk of complications from the flu is greater in the later stages of pregnancy and after childbirth (i.e., up to 6 weeks after birth), it is particularly important for women who are in the 2nd and 3rd trimesters, women in labour, and women up to 6 weeks after delivery to receive treatment with antivirals within 48 hours of the onset of symptoms.

Based on existing evidence, antivirals oseltamivir (Tamiflu®) and zanamivir (Relenza®) are not associated with an increased risk of adverse effects in the mother or unborn child.

Guidelines on the Treatment of Seasonal Influenza

The Association of Medical Microbiology and Infectious Diseases Canada (AMMI) released guidelines on the vaccination and treatment of seasonal influenza. The AOM has not reviewed the evidence upon which its recommendations are based.  The guidelines make the following conclusions of relevance to midwives:

  • “The rates of hospitalization [of healthy pregnant women with influenza] were comparable to those observed in individuals with other recognized co-morbid conditions that increase the risk of influenza-related complications. As a result of such data, pregnancy is now recognized as a risk factor that warrants annual influenza immunization.”
  • “During the 2009 A(H1N1)pdm09 pandemic, not only were increased rates of hospitalization observed in healthy pregnant women, especially in the second and third trimester, but also an increased rate of death compared to that in non-pregnant women… A recent meta-analysis demonstrated that women who were less than four weeks post-partum were at greatest risk of death. New evidence indicates that there is a significant increase in stillbirths, premature deliveries, and infant mortality when women have influenza in the third trimester.”
  • “Oseltamivir in standard doses is recommended for treatment of pregnant women with influenza based on the extensive safe use of oseltamivir to treat pregnant women during the 2009 H1N1 pandemic.”
  • For adults with risk factors (including pregnancy), presenting with mild or uncomplicated influenza, physicians should initiate oseltamivir if within 48 hours of symptom onset. Treatment should be considered if after 48 hours.

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.