key: cord-0874796-h4lbinv9
authors: Eid, Joe; Abdelwahab, Mahmoud; Caplan, Madeleine; Bilbe, Caroline; Hajmurad, Sema; Costantine, Maged M.; Rood, Kara M.
title: Increasing oxygen requirements and disease severity in pregnant individuals with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Delta variant
date: 2022-03-10
journal: Am J Obstet Gynecol MFM
DOI: 10.1016/j.ajogmf.2022.100612
sha: 1d3c946823eb7873596482dedeca225e5936eb96
doc_id: 874796
cord_uid: h4lbinv9

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According to the Centers for Disease Control and Prevention (CDC), the Delta (B.1.617.2) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) became the most common variant in certain regions of the United States in July 2021. More than 80% of cases detected in Ohio starting the first week of July were attributed to the Delta variant 1 .

While in the non-pregnant population the Delta variant was associated with increase in disease severity and oxygen requirement 2 , there are limited data on its impact on pregnant individuals 3,4 . The objective of our study was to determine whether the Delta variant was associated with increased oxygen requirement and disease severity in our pregnant population.

This is a single academic center retrospective cohort study conducted at The Ohio State University Wexner Medical Center. All pregnant individuals who had a positive molecular test were not routinely sequenced for the different variants at our institution.

Our primary outcome was need for oxygen supplementation defined as any oxygen supplementation using nasal cannula, high flow nasal cannula, mechanical ventilation, or extracorporeal membrane oxygenation (ECMO). Patients with an oxygen saturation equal or less than 94% on room air, severe or critical disease were started on oxygen supplementation 3 (criteria applied across all time points during study period). Secondary outcomes included disease severity based on the National Institutes of Health criteria (assigned at time of diagnosis or hospital admission) 5 , hospitalization for COVID-19, COVID-19 symptoms, laboratory and imaging abnormalities, intensive care unit (ICU) admission, inpatient therapeutics use including remdesivir, and corticosteroids, and maternal death. A subgroup analysis was performed comparing outcomes for vaccinated and unvaccinated individuals in the Delta variant cohort.

Clinical care of patients was similar regardless of vaccination status.

Summary statistics were calculated for baseline variables. Bivariate analyses were performed as appropriate. The association between infection with the Delta variant and the primary and secondary outcomes was determined using multivariable analysis correcting for clinically relevant covariates such as body mass index (BMI) and major medical comorbidity (respiratory disease, hypertension and pregestational diabetes), and expressed as adjusted odds ratio with 95% confidence interval. All statistical analyses were performed using Stata version 15 (StataCorp, College Station, TX). P-value less than 0.05 was used for statistical significance. As this was an exploratory study with convenience sampling, no power calculations or correction for multiple comparisons were performed. This study was approved by University's Institutional Review Board.

A total of 424 pregnant individuals tested positive for SARS-CoV-2 infection during the study period and were included. Maternal characteristics including age, BMI, gestational age at COVID-19 diagnosis, and medical comorbidities were comparable between the pre-Delta and the Delta groups (Table 1) . Patients in the Pre-Delta group had higher rates of gestational diabetes and were more likely to be delivered by cesarean section; while no difference was noted in rates of hypertensive diseases of pregnancy or preterm delivery between the two groups (Table 1) .

Patients in the Delta variant group were more likely to require any form of oxygen supplementation (18.2% vs 6.8%, aOR 2.76, 95% CI 1.38-5.50) and have more severe disease (moderate, severe, or critical; 23.2% vs 10.5%, aOR 2.30, 95% CI 1.24-4.21) compared with those in the pre-Delta variant group (Table 2) . Additionally, they were more likely to have laboratory or imaging abnormalities and require admission to the ICU (Table 2 ). There were two maternal deaths in the Delta variant group compared with none in the pre-Delta variant group.

Both patients were unvaccinated.

The rate of COVID-19 vaccination was higher in the Delta variant group, with 17.2% of patients completed vaccination series compared with 6.2% in the pre-Delta variant group (Table 1) . A subgroup analysis among COVID-19 patients in the Delta variant cohort showed that none of the vaccinated patients required oxygen supplementation compared to 22% (p=0.04) of the unvaccinated patients who also showed more severe forms of the disease (moderate, severe, or critical; 26% vs 0%, p=0.01). In addition, the rates of laboratory or imaging abnormalities (30.5% vs 5.9%, p=0.04) and admission to the hospital (22% vs 0%, p=0.04) were all significantly higher in unvaccinated pregnant individuals with the Delta variant compared with those unvaccinated (Table 2) https://www.covid19treatmentguidelines.nih.gov/overview/clinical-spectrum/ 

aOR-adjusted odds ratio for obesity (Body mass index>30) and co-occuring medical conditions (respiratory disease, chronic hypertension and pre-gestational diabetes)

Abbreviations: ICU, intensive care unit

HFNC, high flow nasal cannula

ECMO, extracorporeal membrane oxygenation

Mild illness: Symptomatic without shortness of breath/dyspnea/abnormal chest imaging, Moderate illness: evidence of lower respiratory disease during clinical assessment or imaging and who have an oxygen saturation (SpO2) ≥94%, Severe illness: SpO2 <94% on room air at sea level, a ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2/FiO2) <300 mm Hg, a respiratory rate >30 breaths/min, or lung infiltrates >50%

c Laboratory abnormalities: Defined as platelet count less than 150 10*3/uL, or prothrombin time greater than 14 seconds or partial prothrombin time greater than 35 seconds, or creatinine greater than 1 mg/dl, or Aspartate aminotransferase greater than 40 units/l or Alanine aminotransferase greater than 35 units/l. Chest imaging abnormalities defined by changes consistent with COVID-19 on chest