Impact of COVID-19 in pregnancy on maternal and perinatal outcomes during the Delta variant period: a comparison of the Delta and pre-delta time periods, 2020-2021.

Background: To describe the impact on maternal and perinatal outcomes of the Delta variant of COVID-19 compared to the pre-Delta period in pregnant women with COVID-19 infections in one large public, non-profit hospital system.

Methods: We conducted a retrospective chart review of identified COVID-19 diagnosed pregnant women with the outcome of pregnancy (livebirth or stillbirths). We assessed maternal and perinatal outcomes between the pre-delta and Delta variant time periods.

Results: A study cohort of 173 mother-baby dyads was identified from January 2020 to November 2021. Maternal outcomes showed a higher rate of cesarean section (33.8%,49%; p = 0.047), with a higher frequency for worsening maternal condition due to COVID-19 (2.8%, 13.7%; p = 0.016) and association with non-reassuring fetal heart tones as indications for cesarean Sect. (53.8%, 95%; p = 0.008) during the Delta time period. There were more preterm births (16.9%, 32.4%; p = 0.023) even when excluding stillbirths (16.9%,30%; p = 0.05). Cesarean section due to "worsening maternal condition" was an independent risk factors for early delivery (β = 2.66, 93.32-62.02, p < 0.001). The neonates had a longer mean (7.1 days, 9.9 days; p < 0.001) and median (2 days, 3 days; p < 0.001) length of stay during the Delta period. There was no difference in Apgar scores, NICU admissions or need for respiratory support between time periods.

Conclusion: In a public, non-profit health system, from January 2020 to November of 2021, mothers with a diagnosis of COVID-19 during pregnancy, there were more preterm deliveries during the Delta time period, as well as longer length of stay for liveborn babies.