Factsheet

Influenza and pregnancy - guidance for clinicians fact sheet

Pregnant women have a higher risk of severe disease than other women following infection with influenza. This factsheet provides guidance for health professionals on managing pregnant women presenting with suspected or confirmed influenza infections.​

Last updated: 16 January 2024

​​​​​Prevention

Flu vaccination

Influenza vaccination is recommended for all pregnant women regardless of gestation, and for women planning pregnancy.

Influenza vaccination during pregnancy should be routine: safety is well established for both mother and baby, and maternal antibody continues to protect the newborn in the critical first few months of life.

The timing of vaccination depends on the time of the year, vaccine availability, stage of pregnancy and the anticipated duration of immunity. Influenza vaccine can be given at the same time as pertussis vaccination (ideally at 28 weeks) but may be given earlier, and should not be delayed if the winter influenza season has begun or is imminent.

For more information, see the Maternal influenza vaccinatio​​n - evidence review.

General precautions

To avoid influenza, pregnant women should also be advised to take sensible precautions including:

  • avoiding close contact with people who have symptoms, if possible
  • washing hands with soap and running water or use an alcohol based hand rub after contact with symptomatic people or their secretions
  • encourage symptomatic people in the household to keep at least 1 metre away and follow cough etiquette and good hand hygiene
  • avoid large, crowded gatherings during the influenza season.

There is no recommendation for well women to wear surgical masks, or to exclude themselves from regular activities.

Prophylaxis

Antiviral prophylaxis is not generally recommended for pregnant women, except in specific circumstances. For example, it may be considered in a pregnant woman who has had close contact with a patient with confirmed influenza, especially in the second or third trimester and in the presence of other co-morbidities.

Influenza-like illness (ILI)

For the purpose of this guidance, ILI is defined as a history of a fever (or temperature >38.0 C), and either a cough or sore throat. Pregnant women should be encouraged to present early if they develop an ILI, or if they develop any respiratory symptoms after close contact with a person who has an ILI. They should be assessed, diagnosed and managed on clinical grounds, noting that there are several differential diagnoses for people presenting with an ILI. Influenza typically involves other symptoms such as fatigue, headache, muscle aches and pains, and is more likely to be the cause of this constellation of symptoms during the influenza season.

Testing and treatment

The optimal laboratory test for influenza in an adult is a nasopharyngeal swab using virual or universal transport media. Viral respiratory screen should be requested – most NSW hospitals can provide a result within hours.

During influenza season treatment of pregnant women with ILI should not be delayed while awaiting test results. Treatment can be commenced on presentation with typical ILI symptoms, and suspended if laboratory testing is negative for influenza. Treatment with anti-influenza medicine (either oseltamivir [Tamiflu®] or zanamivir [Relenza®]) may be offered to pregnant woman at any stage of pregnancy. Although both drugs are classified as B1 (limited data indicating safety in pregnancy), use in pregnant women to date (mostly in second and third trimester) has not been associated with adverse fetal outcomes.

Experience of anti-influenza medication use in the first trimester of pregnancy remains very limited, so a careful discussion of the potential risks and benefits is essential before prescribing such agents. Experts have differing views as to the best drug to use in pregnancy: oseltamivir is a capsule, has a systemic effect but causes nausea and vomiting in some patients; zanamivir is inhaled, has a direct effect on the target organ (the lung) but can cause bronchospasm in some patients.

Considerations in the management of influenza in each trimester

First trimester

In the first trimester, the concern is largely about the effect the mother’s fever may have on the developing fetus, including miscarriage. Note that:

  • symptomatic treatment with paracetamol is recommended to reduce fever
  • treatment with anti-influenza medicine should be discussed with the mother, taking into account other conditions that may increase her risk of severe disease.

Second and third trimester

In the second and third trimesters, the concern is largely for severity of illness in the mother, as well as the potential effects of the mother’s fever on the developing fetus. Note that:

  • treatment with anti-influenza medicine is strongly recommended to reduce the severity of disease in the mother
  • symptomatic treatment with paracetamol is recommended to reduce fever
  • assessment of maternal and fetal wellbeing is recommended at every presentation.

Around the time of birth

Around the time of birth, the concern is about both the severity of illness in the mother and the risk of transmission to the baby. Note that:

  • treatment with anti-influenza medicine of the mother is strongly recommended to reduce the severity of disease
  • symptomatic treatment with paracetamol is recommended to reduce fever
  • while the baby is <3 months old, treatment of the mother is also recommended to reduce the risk of transmission to the baby
  • the mother should not be asked to wear a mask during labour and birth, but others in the room should follow infection control guidelines
  • there is usually no advantage in expediting the birth of the baby.

Minimising the risk of infection from mother to baby

The spectrum of disease of influenza in newborns is unclear but serious infections occur.

Sensible efforts should be made to reduce the likelihood the baby will be infected from an infected mother, while minimising the effect on the mother-baby relationship. These include:

  • treating the mother to reduce the risk of transmission (the mother is considered noninfectious after 72 hours of treatment with anti-influenza medicine)
  • the mother and baby sleep at least 1 metre apart, in the same room (at least while in hospital), and in separate beds
  • advising the mother to avoid coughing and practice cough etiquette near the baby.

Breast feeding should be strongly encouraged. When breast feeding, bathing, caring for, cuddling, or otherwise being within 1 metre of the baby, the mother should:

  • wear a surgical mask
  • wash her hands thoroughly with soap and water before interacting with the baby.

These measures should apply to any carer or family member with influenza if it is essential that they interact with the baby.

Although these measures can be ceased when the mother is no longer infectious, continued good hygiene should be encouraged at all times.

Mothers requiring hospital care should not be prematurely discharged because they have influenza.

If discharged while still infectious, mothers should be provided with a sufficient supply of surgical masks to take home.

Prophylaxis is not recommended for the baby. Should the baby develop symptoms, the baby should be isolated from other babies, assessed urgently by a paediatrician, and if influenza is diagnosed, considered for treatment with anti-influenza medicine.

Summary of strategies to manage pregnant women with influenza or ILI and to minimise influenza transmission in healthcare settings

Prevention

  • Avoiding close contact with people who have influenza or influenza-like illness (ILI).
  • Washing hands with soap and running water or use an alcohol based hand rub.
  • Vaccinating with influenza vaccine.
  • Instructing household contacts on respiratory etiquette, good hand washing and avoidance of close contact with the pregnant woman.

Screening of patients and visitors during influenza season

  • Passive screening for influenza-like illness (ILI) of all maternity patients and visitors, using appropriate signage at hospital entrances and entrances to ‘very high risk’ and ‘high risk’ areas including intensive care units (including neonatal intensive care), high dependency units, emergency departments, antenatal clinics, antenatal and postnatal wards, and birthing units.
  • Monitoring all inpatients for development of ILI by clinicians keeping a high index of suspicion.
  • Clinicians to have a high index of suspicion for influenza in any patient presenting with a fever and/or respiratory symptoms with early treatment with anti- influenza medications recommended.

Infection control measures

  • Isolating or cohorting maternal influenza cases.
  • With maternal influenza cases avoiding mother-baby separation but ensuring:
    • careful handwashing and wearing of a mask to minimise the risk of influenza transmission to baby during close contact (e.g. breastfeeding, bathing, nappy changing etc.) and
    • spatial separation (> 1 metre) of mothers and babies at other times.
  • Staff using appropriate PPE.
  • Ensuring appropriate environmental cleaning of rooms and other settings where infectious patients have been.

Management of cases, visitors and accompanying persons

  • Isolating or cohorting maternal influenza cases.
  • Educating influenza patients in respiratory etiquette and hand hygiene.
  • Isolating cases for 7 days if not on anti-influenza medications, and 3 days if taking medication.
  • Providing maternal and fetal surveillance for pregnant inpatients in other parts of the hospital.
  • Discouraging unwell visitors to all maternity care areas including ambulatory settings, inpatient settings, birthing units, and newborn nurseries.

Communication

  • Communicating to all stakeholders (staff, patients and others)
  • Use of standardised signage.

Current as at: Tuesday 16 January 2024
Contact page owner: Vaccine Preventable Diseases