Paxlovid Use in Pregnancy
Paxlovid (nirmatrelvir/ritonavir) can be used in pregnancy for mild-to-moderate COVID-19 when initiated within 5 days of symptom onset, as pregnant women are at high risk for severe COVID-19 outcomes and the available evidence demonstrates safety with low rates of adverse maternal and neonatal outcomes. 1
Clinical Decision-Making Framework
When to prescribe:
- Pregnant women with mild-to-moderate COVID-19 within 5 days of symptom onset 2
- Presence of risk factors for severe COVID-19 (63.8% of treated patients had comorbidities in addition to pregnancy) 3
- After shared decision-making discussion about potential risks and benefits 1
Multidisciplinary involvement:
- Involve obstetrics and infectious disease specialists in treatment decisions 1
- Consider hepatology consultation if indicated 1
Safety Profile
Maternal outcomes demonstrate favorable safety:
- Hospitalization rate: 2% (95% CI: 1%-5%) 2
- Drug discontinuation due to adverse effects: 0.7-4.3% 2, 4
- No maternal deaths reported across studies 2
- Treatment completion rate: 95.7% 3
Common adverse effects (generally mild):
- Dysgeusia (altered taste): 91.7% of patients 4
- Diarrhea: common but specific rate varies 5
- These side effects are typically self-limited and do not require treatment discontinuation 5
Neonatal outcomes:
- Mean birth weight: 3186 g (95% CI: 3123-3248 g) 2
- No neonatal deaths reported 2
- Possible increased rate of small-for-gestational-age infants (23.08% vs 3.57%, p=0.086), though not statistically significant 5
- No serious adverse neonatal effects observed 3
Clinical Efficacy
Symptom duration:
- Significantly shorter duration of COVID-19 symptoms: 10.1 days vs 15.6 days in untreated patients (p=0.04) 5
- Low hospitalization rates suggest effective prevention of disease progression 2
Rebound phenomenon:
- COVID-19 rebound occurs in approximately 50% of patients (positive test result in 50%, symptom return in 33.3%) 4
- This rebound rate is consistent with non-pregnant populations and does not indicate treatment failure 4
Important Clinical Considerations
Timing of initiation:
- Start treatment within 5 days of symptom onset for optimal efficacy 2
- Median time to initiation in successful cases: 1 day after symptom onset (range 0-5 days) 3
Delivery considerations:
- Higher cesarean delivery rate observed in treated patients (76.92% vs 42.86%, p=0.042) 5
- Most cesarean deliveries were scheduled rather than emergent (75% of cesarean deliveries) 3
- This finding may reflect underlying maternal comorbidities rather than drug effect 5
Gestational diabetes and hypertension monitoring:
- New-onset gestational diabetes: 4.0% (95% CI: 1%-16%) 2
- New-onset gestational hypertension: 4% (95% CI: 1%-26%) 2
- Monitor for these conditions, though rates are within expected ranges for pregnant populations 2
Rationale for Use Based on Component Drugs
Ritonavir safety data:
- Extensive experience with ritonavir use in HIV-positive pregnant women as part of HAART therapy shows no significant teratogenicity 6
- Ritonavir-boosted protease inhibitors (atazanavir/ritonavir, darunavir/ritonavir) are recommended options during pregnancy for HIV treatment 7
Nirmatrelvir preclinical data:
- Animal studies show no evidence of teratogenicity 6
Common Pitfalls to Avoid
- Do not delay treatment while awaiting specialist consultation if patient meets criteria and is within the 5-day window 2
- Do not withhold treatment solely due to unknown long-term data, as pregnant women face substantially higher COVID-19 morbidity and mortality risks 3
- Do not assume rebound indicates treatment failure or requires retreatment; this is a known phenomenon 4
- Counsel patients preemptively about dysgeusia to prevent premature discontinuation 4