Risk for Stillbirth Among Women With and Without COVID-19 at Delivery Hospitalization - United States, March 2020-September 2021

MMWR Morb Mortal Wkly Rep. 2021 Nov 26;70(47):1640-1645. doi: 10.15585/mmwr.mm7047e1.


Pregnant women are at increased risk for severe COVID-19-related illness, and COVID-19 is associated with an increased risk for adverse pregnancy outcomes and maternal and neonatal complications (1-3). To date, studies assessing whether COVID-19 during pregnancy is associated with increased risk for stillbirth have yielded mixed results (2-4). Since the B.1.617.2 (Delta) variant of SARS-CoV-2 (the virus that causes COVID-19) became the predominant circulating variant,* there have been anecdotal reports of increasing rates of stillbirths in women with COVID-19. CDC used the Premier Healthcare Database Special COVID-19 Release (PHD-SR), a large hospital-based administrative database,§ to assess whether a maternal COVID-19 diagnosis documented at delivery hospitalization was associated with stillbirth during March 2020-September 2021 as well as before and during the period of Delta variant predominance in the United States (March 2020-June 2021 and July-September 2021, respectively). Among 1,249,634 deliveries during March 2020-September 2021, stillbirths were rare (8,154; 0.65%): 273 (1.26%) occurred among 21,653 deliveries to women with COVID-19 documented at the delivery hospitalization, and 7,881 (0.64%) occurred among 1,227,981 deliveries without COVID-19. The adjusted risk for stillbirth was higher in deliveries with COVID-19 compared with deliveries without COVID-19 during March 2020-September 2021 (adjusted relative risk [aRR] = 1.90; 95% CI = 1.69-2.15), including during the pre-Delta (aRR = 1.47; 95% CI = 1.27-1.71) and Delta periods (aRR = 4.04; 95% CI = 3.28-4.97). COVID-19 documented at delivery was associated with increased risk for stillbirth, with a stronger association during the period of Delta variant predominance. Implementing evidence-based COVID-19 prevention strategies, including vaccination before or during pregnancy, is critical to reducing the impact of COVID-19 on stillbirths.

MeSH terms

  • Adult
  • COVID-19 / epidemiology*
  • Delivery, Obstetric
  • Female
  • Hospitalization
  • Humans
  • Pregnancy
  • Pregnancy Complications, Infectious / epidemiology*
  • Risk Assessment
  • Stillbirth / epidemiology*
  • United States / epidemiology