Management of Influenza in Pregnancy

Antiviral Treatment

The American Academy of Pediatrics recommends oseltamivir dosing of 75 mg orally twice daily for 5 days for pregnant women with suspected or confirmed influenza 1, 2, 3
Alternative option: Zanamivir 10 mg (two 5 mg inhalations) twice daily for 5 days can be used if oseltamivir is contraindicated 3

Safety Profile in First Trimester

The American Academy of Pediatrics found no association between first trimester influenza vaccination and major congenital malformations in a 5-year retrospective cohort of over 10,000 women 1, 2, 4, 5
A systematic review and meta-analysis of 15 studies showed no association between congenital defects and influenza vaccination in any trimester, including the first 1, 2, 4

Clinical Rationale for Aggressive Treatment

Pregnant women are at higher risk for severe illness, pneumonia, ICU admission, and death compared to non-pregnant women, according to the CDC 6, 7
The relative risk for hospitalization increases from 1.4 during weeks 14-20 of gestation to 4.7 during weeks 37-42, as reported by the CDC 8
Influenza infection during pregnancy is associated with increased odds of congenital anomalies, stillbirth, late pregnancy loss, preterm delivery, low birth weight, and small-for-gestational-age infants, according to the American Journal of Obstetrics and Gynecology 9

Vaccination Recommendations

The CDC recommends that all pregnant women receive inactivated influenza vaccine (IIV) during any trimester, including the first trimester 6, 7
Any licensed, recommended, age-appropriate inactivated influenza vaccine (IIV3 or IIV4) or recombinant influenza vaccine (RIV3 or RIV4) may be used, according to the CDC 6, 7
Live attenuated influenza vaccine (LAIV) is contraindicated during pregnancy, as recommended by the American Academy of Pediatrics and the CDC 1, 2, 4, 7

Symptomatic Management of Cough

Adequate hydration and rest are essential supportive measures for pregnant women with influenza, as recommended by the American Academy of Pediatrics 1
Monitor for warning signs requiring urgent evaluation: difficulty breathing, chest pain, persistent high fever, decreased fetal movement, or signs of preterm labor, as recommended by the American Academy of Pediatrics 4

Treatment of Influenza in Pregnant Women

First-Line Treatment Recommendations

The American Academy of Pediatrics recommends standard adult dosing for oseltamivir, which is 75 mg twice daily for 5 days 10

Safety Profile of Oseltamir During Pregnancy

The Centers for Disease Control and Prevention notes that the most common side effects of oseltamivir are nausea and vomiting, which occur in approximately 10% and 9% of patients, respectively 11

Alternative Treatment Options

The American Academy of Pediatrics states that baloxavir marboxil has been approved for treatment of uncomplicated influenza in outpatients 12 years and older, but data on its use during pregnancy is limited 10

Prevention Through Vaccination

The American Academy of Pediatrics strongly recommends influenza vaccination for all pregnant women during any trimester, which protects both the mother and infant through transplacental antibody transfer and breastfeeding 12
The American Academy of Pediatrics also notes that infants born to vaccinated mothers have a risk reduction of up to 72% for laboratory-confirmed influenza hospitalization in the first few months of life 12

Influenza Vaccination in Preconception and Pregnancy

Rationale for Influenza Vaccination

The CDC and ACOG recommend that all individuals who are or will be pregnant during influenza season receive inactivated influenza vaccine (IIV) as soon as it is available, ideally by the end of October 13
Vaccination can be administered during any trimester of pregnancy, including the first trimester, with substantial safety data supporting this practice 14, 13
While Rubella and Varicella vaccines are contraindicated during pregnancy, they should be given during preconception if the patient is non-immune, but require waiting at least 28 days before attempting conception after administration 13

Vaccine Administration and Safety

Any licensed, age-appropriate inactivated influenza vaccine (IIV3 or IIV4) or recombinant influenza vaccine (RIV3 or RIV4) may be used 13
Live attenuated influenza vaccine (LAIV) is contraindicated during pregnancy but can be used postpartum 13

Preconception Planning

Do not delay vaccination waiting for pregnancy confirmation - if planning winter conception, vaccinate as soon as seasonal vaccine becomes available 13
Annual vaccination is required due to antigenic drift and waning immunity 13

Influenza Vaccine Administration in Third Trimester

Primary Recommendation

The American College of Obstetricians and Gynecologists and ACIP recommend that all pregnant persons receive influenza vaccine during any trimester of pregnancy, including the third trimester, as the vaccine can be administered at any time during pregnancy, before and during the influenza season 15, 16

Specific Advantages of Third Trimester Vaccination

Early vaccination during July and August should be considered for persons in their third trimester because this provides protection for the infant during the first months of life when they are too young to be vaccinated 15, 16

Clinical Rationale for Third Trimester Vaccination

The relative risk for hospitalization increases dramatically from 1.4 during weeks 14-20 of gestation to 4.7 during weeks 37-42, indicating a substantially elevated risk during the third trimester 17, 18
Pregnant and postpartum persons are at higher risk for severe illness and complications from influenza, particularly during the second and third trimesters 15, 16

Vaccine Types Appropriate for Third Trimester

Inactivated influenza vaccine (IIV3) or recombinant influenza vaccine (RIV3) can be used safely during the third trimester 15, 16
Live attenuated influenza vaccine (LAIV3) is contraindicated during pregnancy but can be used postpartum 15, 16

Safety Profile

Studies of influenza vaccination in more than 2,000 pregnant women have demonstrated no adverse fetal effects 17, 18
Most studies have not noted any association between influenza vaccination and adverse pregnancy outcomes 15, 16

Practical Implementation

For women in their third trimester during July-August when vaccine first becomes available, do not delay vaccination—early administration maximizes infant protection through transplacental antibody transfer 15, 16
Vaccination at any point in the third trimester provides benefit and should not be delayed 15, 16

Treatment of Influenza in Pregnant Women

Risks and Complications

Pregnant women show disproportionately high death rates during influenza pandemics, with a substantially higher maternal mortality risk 19
Fetal complications include increased odds of congenital anomalies, stillbirth, late pregnancy loss, preterm delivery, low birth weight, and small-for-gestational-age infants 19

Prevention and Vaccination

The American College of Obstetricians and Gynecologists recommends that live attenuated influenza vaccine (LAIV, intranasal) is contraindicated during pregnancy 20
Vaccination provides dual protection, reducing the risk of severe influenza illness, hospitalization, and complications in pregnant women, and up to 72% risk reduction for laboratory-confirmed influenza hospitalization in infants born to vaccinated mothers 19

Management of Influenza in Pregnant Women

Clinical Rationale for Aggressive Treatment

Pregnant women face disproportionately high death rates during influenza pandemics, with relative risk for hospitalization increasing from 1.4 at weeks 14-20 of gestation to 4.7 at weeks 37-42 compared to postpartum women, according to the Centers for Disease Control and Prevention (CDC) 21, 22, 23, 24, 25
Pregnancy increases susceptibility to influenza through increases in heart rate, stroke volume, and oxygen consumption; decreases in lung capacity; and changes in immunologic function, as reported by the CDC 21, 22, 23

Supportive Care Measures

Aspirin is contraindicated in pregnancy, particularly in children and teenagers due to Reye syndrome risk, as stated by the CDC 21

Monitoring for Warning Signs

Chest pain or pressure is a warning sign that requires urgent evaluation, according to the CDC 21
Persistent high fever despite acetaminophen is a warning sign that requires urgent evaluation, as reported by the CDC 25

Clinical Rationale for Aggressive Treatment

The relative risk for hospitalization escalates from 1.4 at weeks 14-20 of gestation to 4.7 at weeks 37-42 compared to postpartum women, according to the Centers for Disease Control and Prevention (CDC) 26, 27, 28
Third-trimester pregnant women have hospitalization rates (250/100,000) comparable to non-pregnant individuals with high-risk medical conditions, as reported by the CDC 27
Physiologic changes in pregnancy increase vulnerability: elevated heart rate and stroke volume, increased oxygen consumption, decreased lung capacity, and altered immunologic function, as noted by the CDC 26, 28
Pregnant women with underlying conditions like asthma or heart disease face even higher risks and require treatment regardless of trimester, according to the CDC 26, 28, 29