ABSTRACT
BACKGROUND: Information on the severity of coronavirus disease 2019 (COVID-19) attributable to the Delta variant in the United States among pregnant people is limited. We assessed the risk for severe COVID-19 by pregnancy status in the period of Delta variant predominance compared with the pre-Delta period. METHODS: Laboratory-confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections among symptomatic women of reproductive age (WRA) were assessed. We calculated adjusted risk ratios for severe disease including intensive care unit (ICU) admission, receipt of invasive ventilation or extracorporeal membrane oxygenation (ECMO), and death comparing the pre-Delta period (1 January 2020-26 June 2021) and the Delta period (27 June 2021-25 December 2021) for pregnant and nonpregnant WRA. RESULTS: Compared with the pre-Delta period, the risk of ICU admission during the Delta period was 41% higher (adjusted risk ratio [aRR], 1.41 [95% confidence interval {CI}, 1.17-1.69]) for pregnant WRA and 9% higher (aRR, 1.09 [95% CI, 1.00-1.18]) for nonpregnant WRA. The risk of invasive ventilation or ECMO was higher for pregnant (aRR, 1.83 [95% CI, 1.26-2.65]) and nonpregnant (aRR, 1.34 [95% CI, 1.17-1.54]) WRA in the Delta period. During the Delta period, the risk of death was 3.33 (95% CI, 2.48-4.46) times the risk in the pre-Delta period among pregnant WRA and 1.62 (95% CI, 1.49-1.77) among nonpregnant WRA. CONCLUSIONS: Compared with the pre-Delta period, pregnant and nonpregnant WRA were at increased risk for severe COVID-19 in the Delta period.