Is Tamiflu Safe for Pregnancy?
Yes, oseltamivir (Tamiflu) is safe and strongly recommended for pregnant women with suspected or confirmed influenza, and should be started immediately without waiting for laboratory confirmation. 1, 2
Primary Recommendation
The American College of Obstetricians and Gynecologists and CDC explicitly recommend oseltamivir 75 mg orally twice daily for 5 days for any pregnant woman with suspected or confirmed influenza, regardless of trimester or vaccination status. 1 Pregnancy is explicitly not a contraindication to oseltamivir use. 2
Safety Evidence
The safety profile of oseltamivir in pregnancy is reassuring across multiple data sources:
No adverse effects have been reported among women who received oseltamivir during pregnancy or among infants born to such women, according to extensive post-marketing surveillance. 1, 2
Published observational studies of more than 5,000 pregnant women exposed to oseltamivir, including over 1,000 women in the first trimester, show no increased rate of congenital malformations above the general population. 3
One retrospective cohort study found no association between oseltamivir use during pregnancy and preterm birth, premature rupture of membranes, malformations, or abnormal fetal weight. 2
The CDC found no association between first trimester influenza vaccination and major congenital malformations in a cohort of over 10,000 women. 1
Why Treatment Is Critical
The risks of untreated influenza far outweigh any theoretical medication concerns:
Pregnant women are at higher risk for severe illness, pneumonia, ICU admission, and death compared to non-pregnant women. 1
The relative risk for hospitalization increases from 1.4 during weeks 14-20 of gestation to 4.7 during weeks 37-42. 1
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. 1
Fever itself poses risks to fetal development, so treating influenza with oseltamivir may actually reduce fetal risk by shortening illness duration and reducing fever. 1
Practical Treatment Details
Start treatment immediately upon suspicion—do not wait for laboratory confirmation or the 48-hour window. 1, 4 While treatment within 48 hours is ideal, it should not be withheld if this window is missed. 4
Use the same adult dosing: 75 mg orally twice daily for 5 days. 1, 2
Take oseltamivir with food to significantly reduce nausea and vomiting, the most common side effects (occurring in approximately 10% and 9% of patients, respectively). 1, 2
Alternative Option
Zanamivir 10 mg (two 5 mg inhalations) twice daily for 5 days can be used if oseltamivir is contraindicated or unavailable, though oseltamivir remains first-line. 1
Zanamivir has limited systemic absorption but carries potential respiratory complications, particularly in women with underlying respiratory conditions. 1
Post-Exposure Prophylaxis
- For pregnant women with high-risk or moderate-risk exposure to influenza, oseltamivir 75 mg once daily for 7-10 days after last exposure is recommended. 1
Important Caveat About FDA Classification
- The FDA classifies oseltamivir as Pregnancy Category C due to lack of controlled clinical trials, but extensive post-marketing surveillance and observational data demonstrate reassuring safety outcomes. 1 This cautious FDA language predated the 2009 H1N1 pandemic experience, which demonstrated both the severe risks of influenza in pregnancy and the safety profile of oseltamivir. 2