Is Xofluza Safe During Pregnancy?
Xofluza (baloxavir marboxil) lacks adequate data from human studies to confirm its safety in pregnancy. Animal studies show no direct harm to the fetus, but limited human evidence means risks to the developing baby are unknown.[1][2] The manufacturer recommends avoiding it unless benefits outweigh potential risks, and it's classified under FDA Pregnancy Category Not Assigned due to insufficient data.[3]
What Do Clinical Guidelines Say?
CDC and ACOG guidelines prioritize flu prevention in pregnancy but do not specifically endorse Xofluza. They favor oseltamivir (Tamiflu) as first-line treatment for pregnant patients with influenza, citing more established safety data from human exposures.[1][4] Xofluza is approved for acute flu treatment in ages 5+ but carries a warning to consult providers for pregnant or breastfeeding patients.
What Happens in Animal Studies?
Reproductive toxicity studies in rats and rabbits at doses up to 49 times the human exposure found no fetal abnormalities, malformations, or impaired fertility. However, these results do not predict human outcomes, as metabolism differs.[2][5]
Alternatives for Pregnant Women with Flu
- Oseltamivir (Tamiflu): Preferred; extensive data from over 1,000 pregnancies show no increased birth defect risk.[4]
- Zanamivir (Relenza): Inhaled option with minimal systemic absorption; considered safe but less studied.[1]
- Supportive care (rest, hydration, fever control) plus vaccination remain key for all pregnant patients.
Breastfeeding Considerations
Xofluza passes into milk in animal models; human data is absent. Weigh risks, as flu itself poses greater threats to infants.[2][3] Providers may suggest pumping and discarding milk temporarily.
When to Talk to Your Doctor
Discuss immediately if you took Xofluza unknowingly or have flu symptoms while pregnant. They assess gestational age, flu severity, and alternatives. Report exposures to registries like the Antiviral Pregnancy Registry for ongoing safety tracking.[5]
Sources
[1]: CDC Flu Treatment Guidelines
[2]: Xofluza Prescribing Information
[3]: Drugs.com - Xofluza Pregnancy
[4]: ACOG Influenza in Pregnancy
[5]: MotherToBaby - Baloxavir