From the Guidelines
Paxlovid can be considered for use during pregnancy if the potential benefits outweigh the risks, as it may reduce the risk of disease progression and severe COVID-19 outcomes. The World Health Organization (WHO) guidelines suggest that nirmatrelvir/ritonavir represents an option for pregnant people with COVID-19, despite acknowledging uncertainty in terms of potential serious adverse reactions in pregnant or breastfeeding people 1. It is essential to note that ritonavir, a component of Paxlovid, can interact with many drugs, and its twice-daily administration involves doubling the ritonavir dose relative to most modern antiretroviral regimens, which may lead to more easily managed drug-drug interactions with short durations of treatment 1.
Some key points to consider when using Paxlovid during pregnancy include:
- The medication consists of nirmatrelvir and ritonavir tablets taken together twice daily for 5 days
- The standard adult dose is 300 mg nirmatrelvir with 100 mg ritonavir taken together orally every 12 hours
- Treatment should begin as soon as possible after COVID-19 diagnosis and within 5 days of symptom onset
- Pregnant individuals are at higher risk for severe COVID-19, and Paxlovid can reduce the risk of hospitalization and death
- Animal studies showed some potential fetal risks, though at doses higher than human therapeutic doses 1
It is crucial to discuss the use of Paxlovid during pregnancy with a healthcare provider, as they can evaluate the potential benefits and risks and assess any potential drug interactions that need to be managed 1.
From the FDA Drug Label
Available data on the use of nirmatrelvir during pregnancy are insufficient to evaluate for a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. In an embryo-fetal development study with nirmatrelvir, reduced fetal body weights following oral administration of nirmatrelvir to pregnant rabbits were observed at systemic exposures (AUC) approximately 11 times higher than clinical exposure at the approved human dose of PAXLOVID The estimated background risk of major birth defects and miscarriage for the indicated population is unknown.
Paxlovid Safety in Pregnancy: The safety of Paxlovid (nirmatrelvir/ritonavir) during pregnancy is not well established due to insufficient data.
- Key Findings:
- Insufficient data to evaluate drug-associated risks
- Reduced fetal body weights observed in animal studies at high exposures
- Background risk of major birth defects and miscarriage unknown Based on the available information, Paxlovid should be used during pregnancy only if the potential benefit justifies the potential risk 2.
From the Research
Safety of Paxlovid in Pregnancy
- The safety of Paxlovid (nirmatrelvir/ritonavir) in pregnancy has been investigated in several studies 3, 4, 5, 6, 7.
- A study published in the Journal of Infection and Public Health found that Paxlovid was effective and safe for pregnant women during the Omicron wave of the COVID-19 pandemic, with no severe adverse events due to Paxlovid use observed 3.
- Another study published in Obstetrics and Gynecology found that 91.7% of pregnant women who took Paxlovid experienced dysgeusia and 50.0% had rebound, but there were no significant adverse outcomes 4.
- A scoping review published in Vaccines summarized the available data on Paxlovid use in pregnant and lactating women and found that indirect evidence from ritonavir use in pregnant women with HIV showed no significant teratogenicity, and animal studies on nirmatrelvir did not suggest teratogenicity 5.
- A pharmacokinetic analysis of placental transfer of ritonavir in pregnant rats found that the transfer rate of ritonavir to the placenta, amniotic fluid, and fetus was 20.7%, 13.8%, and 4.7%, respectively, and that accumulation of ritonavir is possible in placenta, amniotic fluid, and fetus 6.
- An overview of antiviral treatments in pregnancy published in Obstetrics and Gynecology Clinics of North America highlighted the need for more research on the use of antivirals in pregnancy, including Paxlovid 7.
Adverse Effects and Outcomes
- Common adverse effects of Paxlovid in pregnant women include dysgeusia and diarrhea 3, 4.
- A higher proportion of caesarean delivery rates was observed among Paxlovid-treated women in one study 3.
- There were no significant adverse outcomes reported in pregnant women who took Paxlovid in another study 4.
- The long-term effects of Paxlovid on pregnant women and their offspring are not yet fully understood and require further study 3, 4, 5.