Risk Factors Associated With COVID-19 Symptoms and Potential Vertical Transmission During Pregnancy: A Retrospective Cohort Study

Objective The COVID-19 pandemic is of special concern for pregnant women. A growing body of evidence suggests the virus can have a deleterious impact upon outcomes related to birth and newborn health. There is a paucity of published research demonstrating the factors that influence disease severity among those who are pregnant, while a growing body of evidence demonstrates that vertical transmission occurs. Our study investigated the impact of maternal characteristics upon COVID-19 outcomes, as well as whether disease severity impacted pregnancy outcomes. Methods We conducted a retrospective cohort study of pregnant women with COVID-19 who were admitted to two public hospitals in our state between April-August, 2020. Pregnancy outcomes and clinical, laboratory, and placental data were collected. Results Thirty-four pregnant women tested positive for SARS-CoV-2. Among them, 55% (19/34) were symptomatic. Of those who were symptomatic, 68% (13/19) presented with fever and cough. Those with symptoms had a statistically significant higher pregestational mean body mass index (BMI) compared with asymptomatic women (35.7±7.9 vs 26.7±6.9, P=0.004). Screening of biochemical records demonstrated that symptomatic women had lower potassium levels compared with those who were asymptomatic (median: 3.70 mEq/L vs 4.30 mEq/L, P=0.009). The lowest potassium level (3.0 mEq/L) and one of the highest BMIs (42.4 kg/m(2)) was observed in the only case of postpartum mortality among the symptomatic women. We did not observe any influence of maternal COVID-19 severity on placental histopathology/infant health or evidence of vertical transmission. Conclusion High pregestational BMI and lower potassium levels were associated with the presence of COVID-19 symptoms among pregnant women.