Rates of severe pregnancy-related complications and severe maternal illness and death rose significantly amid the COVID-19 pandemic, find two retrospective US studies published late last week in JAMA Network Open.
Role of disrupted obstetric care
In the first study, a team led by a Beth Israel Deaconess Medical Center researcher evaluated pregnancy-related complications, birth outcomes, and length of stay of more than 1.6 million pregnant women who gave birth at 463 US hospitals in the 14 months leading up to the pandemic (Jan 1, 2019, to Feb 28, 2020) and in the first 14 months of the crisis (Mar 1, 2020, to Apr 31, 2021).
The study included 849,544 patients in the prepandemic period and 805,324 during the pandemic. Characteristics were similar in both groups, including age (35 years and older, 18.1% prepandemic, 18.4% pandemic), race (White, 53.7% vs 53.9%, respectively), and health insurance (Medicaid, 43.1% vs 43.0%). Average gestational age at birth was 38.3 weeks during both periods.
During the pandemic, consistent with US Census reports, live births fell 5.2%. Maternal deaths during delivery rose from 5.17 to 8.69 per 100,000 pregnant women (odds ratio [OR], 1.75). Rates of fetal death and stillbirth stayed relatively stable, at about 0.9%, as did rates of preterm and term births (10.7% and 89.3%, respectively). Mode of delivery was similar during both periods (vaginal OR, 1.01; primary cesarean OR, 1.02; vaginal birth after cesarean OR, 0.98; and repeated cesarean OR, 0.96).
Amid the pandemic, the likelihood of gestational high blood pressure (OR, 1.08), obstetric hemorrhage (OR, 1.07), preeclampsia (dangerously high blood pressure; OR, 1.04), and previous diagnosis of chronic high blood pressure (hypertension; OR, 1.06) rose, while length of stay for delivery declined 7% (rate ratio, 0.931), which the researchers said could reflect expedited discharges to minimize in-hospital infection risks.
The odds of sepsis slightly decreased (OR, 0.89), which the authors attributed at least partially to better handwashing and the wearing of face coverings. Preexisting racial and ethnic inequalities in obstetric outcomes were unchanged.
The researchers said that the poorer pandemic outcomes may have been related to substantial disruptions in outpatient prenatal care, including less monitoring for potential complications, limited access to in-person routine care, scarce essential hospital supplies, and avoidance of healthcare settings for fear of COVID-19 infection.
"It is possible that these disruptions and limitations in monitoring via telehealth may have contributed to the slight worsening of pregnancy-related hypertension," they wrote. "Additionally, increased rates of hypertensive disorders may be due to heightened stress provoked by the pandemic, or reluctance to engage in for prenatal care due to concerns about COVID-19 exposure."
In the struggle to provide obstetric services amid rapidly changing recommendations, "the experience of care was dramatically different—especially with respect to restrictive visitation policies, which limited support during a particularly anxiety-provoking hospitalization," the researchers wrote.
"As the nation continues to face ongoing surges, it will be important to mitigate further pandemic-related disruptions on obstetric care and pregnancy outcomes."
Rates of all outcomes worse amid Delta
A second study, this one by Ascension Health and University of Texas at Austin researchers, assessed the risk of COVID-19–related severe maternal illness in 3,129 infected pregnant women and 12,504 uninfected peers giving birth in 32 hospitals affiliated with a single health system in eight US states from March 2020 to January 2022. The median patient age was 29 years.
The study period spanned the dominance of four SARS-CoV-2 strains: wild-type, March to December 2020; Alpha, January to June 2021; Delta, July to November 2021; and Omicron, December 2021 to January 2022. Hospitals were located in Alabama, Florida, Indiana, Maryland, Michigan, New York, Tennessee, and Texas.
The risk of severe maternal respiratory and nonrespiratory illness was significantly greater with the wild-type strain (OR, 2.74) and Alpha (OR, 2.57) but was much higher with Delta (OR, 7.69). Omicron was not associated with higher risk of severe illness.
Similarly, the odds of severe respiratory events for patients with and without SARS-CoV-2 infection were comparable for the wild-type strain (OR, 12.79) and Alpha variant (OR, 15.56), highest for Delta (OR, 28.14), and lowest for Omicron (OR, 7.05).
And the likelihood of severe nonrespiratory maternal illness for infected patients was similar for the wild-type strain (OR, 2.16) and Alpha variant (OR, 1.96) and highest for Delta (OR, 4.65), while it was not significantly higher for Omicron (OR, 1.21).
"The nonrespiratory SMM [severe maternal morbidity] associated with COVID-19 were driven, in part, by higher than expected rates of blood product transfusion during the Delta variant period," the researchers noted. "This finding supports prior reports suggesting higher rates of nonpulmonary complications (eg, postpartum hemorrhage and blood transfusions) in pregnant patients with SARS-CoV-2 infection during gestation than in the general population."
A secondary analysis of only nontransfusion-related severe maternal illnesses showed an increase during the wild-type era (OR, 2.16) and Alpha period (OR, 1.96) and a yet significantly higher rise during Delta (OR, 4.65) but not Omicron.
"These findings highlight the importance of the prevention of SARS-CoV-2 infection in pregnant individuals and the consideration of infection as a risk factor for adverse peripartum maternal outcomes," the authors wrote.
In a related commentary, Emily Adhikari, MD, of the University of Texas Southwestern Medical Center, and Catherine Spong, MD, of Parkland Health and Hospital System in Dallas, decried the exclusion of pregnant women in the early clinical trials of COVID-19 vaccines.
"Inclusion of pregnant patients in early clinical trials of vaccine safety and efficacy, as well as in postmarketing observational studies, is critical to fully understand how to target preventive and therapeutic treatments in people of childbearing age and what infections to prioritize for maternal or neonatal benefit," they wrote.
"Until we move to an environment of inclusion of pregnant individuals in both the design and conduct of studies, optimizing maternal and infant health will continue to lag."