Objective
To evaluate the influence of ABO and Rh blood groups on morbidity among SARS-CoV-2 infected pregnancies.
Design
Prospective observational study.
Setting
78 centers of the Spanish Obstetric Emergency Group.
Population
Pregnant women with SARS-CoV-2 tested with polymerase-chain-reaction between 26-February and 5-November, 2020. A cohort of 1,278 SARS-CoV-2(+) pregnant women was analyzed and a concurrent comparison group of 1,453 SARS-COV-2(-) patients was established.
Methods
Data were collected from medical charts. SARS-COV-2(+) was compared with SARS-COV-2(-) for differences in distribution of blood groups. We performed multivariate analysis, controlling for maternal age and ethnicity, to evaluate association of ABO and Rh blood groups with maternal and perinatal outcomes in SARS-CoV-2(+) patients with adjusted odds ratios (aOR) and 95% confidence intervals (CI).
Main outcomes measures
Medical morbidity: Symptomatic COVID-19 and medical complications. Obstetric outcomes: caesarean delivery, preterm deliveries, preterm premature rupture of membranes (PPROM), hemorrhagic events, pre-eclampsia, maternal and neonatal mortality, stillbirth.
Results
Differences were noted between blood types and Rh for age and ethnicity comparing SARS-CoV-2(+) and SARS-CoV-2(-) groups (p<0.05). Among the SARS-CoV-2(+) cohort, the odds of symptomatic COVID-19 and obstetric hemorrhagic event were higher in Rh+ vs Rh- mothers (aOR 1.48, 95% CI 1.02-2.14, p=0.037, and aOR 8.72, 95% CI 1.20-63.57, p=0.033, respectively), and PPROM were higher among blood type A vs non-A mothers (aOR 2.06, 95% CI 1.01-4.18, p=0.046).
Conclusions
In SARS-CoV-2(+) pregnant women, Rh- status was associated with a lower risk of symptomatic COVID-19, while Rh+ and blood group A were associated with obstetric hemorrhage and PPROM, respectively.
TWEETABLE ABSTRACT
Among pregnant women with SARS-CoV-2, blood group A and Rh+ are associated with medical and obstetric morbidity.
