610 ABO and Rh blood groups and SARS-CoV-2 susceptibility in pregnancy

Objective: Previous studies suggest a relationship between ABO and Rh blood groups and susceptibility to SARS-CoV-2. Infection status in these studies was determined using polymerase chain reaction (PCR) from nasopharyngeal swabs. Antibody testing may be a more accurate method to assess susceptibility since it detects both current and past infection. Universal testing for SARS-CoV-2 in pregnant women, a generally healthy population, will more likely include a higher number of asymptomatic individuals. This is contrary to studies in the non-pregnant population who were more likely to be tested due to symptomatic presentation. Our objective was to correlate ABO and Rh blood groups to SARS-CoV-2 antibody results in pregnant women admitted to labor and delivery (L&D). Study Design: This is a retrospective chart review of women who were admitted to L&D in seven hospitals in the Northwell Health System in New York state between 5/27/20 to 8/23/20. Women with available SARS-CoV-2 antibody results were included in the study. ABO and Rh blood groups were collected for all subjects. Categorical data were analyzed using 2-tailed chi square tests. Results: Of 2930 women with available SARS-CoV-2 antibody results, 448 (15.3%) were seropositive and 2482 (84.7%) were seronegative. The prevalence of A, B, AB and O blood groups were 32.3%, 16%, 4.9% and 46.6% in the antibody positive group and 32.6%, 17.5%, 5% and 44.7% in the antibody negative group. The percentage of Rh positive women was 93.7% and 90.6% in the antibody positive and negative groups, respectively. ABO blood group was not significantly correlated with antibody status, p=0.84. Rh negative women had a statistically significant decrease in SARS-CoV-2 seroprevalence rate, p=0.03. Conclusion: This is the first study to report the association between blood type and SARS-CoV-2 infection in pregnancy. In contrast to other studies, our study found that ABO blood group is not correlated with risk of infection but Rh negative status may be protective. Further studies are necessary to confirm these findings. [Formula presented]