Is Paxlovid (nirmatrelvir/ritonavir) safe for a pregnant woman to take?

Safety of Paxlovid (Nirmatrelvir/Ritonavir) During Pregnancy

Paxlovid (nirmatrelvir/ritonavir) can be safely used in pregnant women with COVID-19, as the benefits of preventing severe disease outweigh the potential risks based on current evidence.

Evidence on Paxlovid Safety in Pregnancy

The FDA drug label for nirmatrelvir provides important safety information regarding pregnancy use 1:

• Available data on nirmatrelvir use during pregnancy are insufficient to fully evaluate drug-associated risks
• Animal studies showed no adverse developmental outcomes at exposures 3 times higher than clinical doses
• Ritonavir (the second component) has extensive pregnancy safety data from HIV treatment showing no increased risk of birth defects
• The antiretroviral pregnancy registry includes over 3,500 first-trimester and 3,500 second/third-trimester exposures to ritonavir with no increased birth defect rates compared to the general population

Clinical Experience with Paxlovid in Pregnancy

Recent research provides real-world evidence on Paxlovid use in pregnant women:

• A 2023 study of 30 pregnant women treated with Paxlovid found it effective in reducing COVID-19 symptom duration (10.1 days vs 15.6 days in untreated women) with no severe adverse events 2
• A case series of 47 pregnant patients treated with Paxlovid showed good tolerability, with only 2 patients (4.3%) discontinuing due to adverse effects 3
• Another study of 11 pregnant patients with mild-to-moderate COVID-19 reported that all patients who completed Paxlovid treatment experienced symptom resolution without requiring additional care 4

Common Side Effects

The most commonly reported side effects in pregnant women taking Paxlovid include:

• Dysgeusia (altered taste) - reported in up to 91.7% of pregnant patients in one study 5
• Diarrhea
• COVID-19 rebound symptoms (reported in approximately 50% of pregnant patients in one small study) 5

Risk-Benefit Assessment

When considering Paxlovid use in pregnancy:

1. COVID-19 infection during pregnancy is associated with increased risks of:

   • Preeclampsia
   • Eclampsia
   • Preterm birth
   • Premature rupture of membranes
   • Venous thromboembolic disease
   • Fetal death 1

2. These risks must be weighed against the limited but reassuring safety data for Paxlovid:

   • No evidence of teratogenicity in animal studies
   • Extensive safety data for ritonavir in pregnancy from HIV treatment
   • Growing clinical experience showing good tolerability

Clinical Recommendation

For pregnant women with COVID-19 who meet criteria for Paxlovid treatment (mild-to-moderate disease with risk factors for progression):

1. Initiate treatment as early as possible, ideally within 5 days of symptom onset
2. Complete the standard 5-day course
3. Monitor for common side effects like dysgeusia and diarrhea
4. Be aware of potential for symptom rebound after completing treatment

The benefits of preventing progression to severe COVID-19 disease in pregnant women likely outweigh the theoretical risks of Paxlovid use, especially given the established safety profile of ritonavir in pregnancy and the absence of concerning signals in available clinical data.