BACKGROUND: Pregnant people are at risk of severe coronavirus disease 2019 (COVID-19) and associated complications. While withholding treatment from pregnant patients is not recommended, little is known about the frequency of antiviral medication use during pregnancy. METHODS: Using Medicaid and commercial insurance databases, we constructed a national claims-based cohort study of pregnant, recently pregnant, and nonpregnant female patients 18-49 years old with an outpatient diagnosis of COVID-19 between 21 December 2021 and 30 September 2022. Outpatient treatment with a recommended antiviral medication was identified within 5 days of diagnosis, using national drug codes in outpatient prescription drug claims. Propensity score-matched prevalence ratios (PRs) were used to compare antiviral treatment by pregnancy status. RESULTS: A total of 412 755 publicly and privately insured patients with COVID-19 were identified, including 33 855 currently pregnant, 2460 recently pregnant, and 376 440 nonpregnant female patients
6.8% had a record of antiviral medication use, including 1.3% of pregnant, 5.4% of recently pregnant, and 7.3% of nonpregnant women. Most commonly ritonavir-boosted nirmatrelvir was administered. The prevalence of antiviral medication use was 67% lower among pregnant patients compared with nonpregnant patients (PR, 0.33 [95% confidence interval, .30-.36]), even among patients with ≥1 high-risk medical condition (0.29 [.25-.33]). Antiviral medication use was slightly lower among recently pregnant women with ≥1 high-risk medical condition than among nonpregnant women with similar conditions (PR, 0.57
[95% confidence interval, .44-.72]). CONCLUSIONS: Despite US clinical guidelines, we observed low rates of outpatient treatment for COVID-19 among pregnant patients, indicating possible missed opportunities to treat COVID-19 illness during pregnancy and lactation.