Abstract
In 2021, the severe acute respiratory syndrome coronavirus 2 Delta variant rapidly
proliferated and became dominant. Some but not all research evidence supports that
Delta was associated with increased maternal risk. The purpose of this study was to
determine whether Delta was associated with risk for cardiac and respiratory complications
in a national sample. Of an estimated 3,495,188 delivery hospitalizations in 2021,
1.8% of pre-Delta deliveries (n = 29,580; January–June) and 2.1% of Delta-period deliveries (n = 37,545; July–December) had a coronavirus disease 2019 (COVID-19) diagnosis. The
Delta period was associated with increased adjusted odds of respiratory complications
(adjusted odds ratio [aOR] = 1.54, 95% CI: 1.41, 1.69) and cardiac severe maternal
morbidity (SMM; aOR = 1.54, 95% CI: 1.40, 1.69). Among deliveries with a COVID-19
diagnosis, the Delta period was associated with a higher incidence of respiratory
complications (8.4 vs. 3.7%) and cardiac SMM (8.4 vs. 3.5%; p < 0.01 for both). These findings corroborate prior clinical studies suggesting that
the Delta strain was associated with an increased maternal population-level clinical
burden.
Key Points
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The Delta strain was associated with an increased maternal population-level clinical
burden.
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The Delta period was associated with an increased risk for cardiac and respiratory
complications.
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Among deliveries with a COVID-19 diagnosis, the Delta period was associated with increased
risk.
Keywords
COVID-19 - Delta variant - maternal outcomes - pregnancy - morbidity
