Association of ABO and Rh blood groups with obstetric outcomes in SARS-CoV-2 infected pregnancies: A prospective study with a multivariate analysis.

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 1278 SARS-CoV-2(+) pregnant women was analyzed and a concurrent comparison group of 1453 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.

The association between SARS-CoV-2 infection and preterm delivery: a prospective study with a multivariable analysis.

BACKGROUND: To determine whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, the cause of COVID-19 disease) exposure in pregnancy, compared to non-exposure, is associated with infection-related obstetric morbidity. METHODS: We conducted a multicentre prospective study in pregnancy based on a universal antenatal screening program for SARS-CoV-2 infection. Throughout Spain 45 hospitals tested all women at admission on delivery ward using polymerase-chain-reaction (PCR) for COVID-19 since late March 2020. The cohort of positive mothers and the concurrent sample of negative mothers was followed up until 6-weeks post-partum. Multivariable logistic regression analysis, adjusting for known confounding variables, determined the adjusted odds ratio (aOR) with 95% confidence intervals (95% CI) of the association of SARS-CoV-2 infection and obstetric outcomes. MAIN OUTCOME MEASURES: Preterm delivery (primary), premature rupture of membranes and neonatal intensive care unit admissions. RESULTS: Among 1009 screened pregnancies, 246 were SARS-CoV-2 positive. Compared to negative mothers (763 cases), SARS-CoV-2 infection increased the odds of preterm birth (34 vs 51, 13.8% vs 6.7%, aOR 2.12, 95% CI 1.32-3.36, p = 0.002); iatrogenic preterm delivery was more frequent in infected women (4.9% vs 1.3%, p = 0.001), while the occurrence of spontaneous preterm deliveries was statistically similar (6.1% vs 4.7%). An increased risk of premature rupture of membranes at term (39 vs 75, 15.8% vs 9.8%, aOR 1.70, 95% CI 1.11-2.57, p = 0.013) and neonatal intensive care unit admissions (23 vs 18, 9.3% vs 2.4%, aOR 4.62, 95% CI 2.43-8.94, p <  0.001) was also observed in positive mothers. CONCLUSION: This prospective multicentre study demonstrated that pregnant women infected with SARS-CoV-2 have more infection-related obstetric morbidity. This hypothesis merits evaluation of a causal association in further research.

Obstetric Outcomes of SARS-CoV-2 Infection in Asymptomatic Pregnant Women.

Around two percent of asymptomatic women in labor test positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Spain. Families and care providers face childbirth with uncertainty. We determined if SARS-CoV-2 infection at delivery among asymptomatic mothers had different obstetric outcomes compared to negative patients. This was a multicenter prospective study based on universal antenatal screening for SARS-CoV-2 infection. A total of 42 hospitals tested women admitted for delivery using polymerase chain reaction, from March to May 2020. We included positive mothers and a sample of negative mothers asymptomatic throughout the antenatal period, with 6-week postpartum follow-up. Association between SARS-CoV-2 and obstetric outcomes was evaluated by multivariate logistic regression analyses. In total, 174 asymptomatic SARS-CoV-2 positive pregnancies were compared with 430 asymptomatic negative pregnancies. No differences were observed between both groups in key maternal and neonatal outcomes at delivery and follow-up, with the exception of prelabor rupture of membranes at term (adjusted odds ratio 1.88, 95% confidence interval 1.13-3.11; p = 0.015). Asymptomatic SARS-CoV-2 positive mothers have higher odds of prelabor rupture of membranes at term, without an increase in perinatal complications, compared to negative mothers. Pregnant women testing positive for SARS-CoV-2 at admission for delivery should be reassured by their healthcare workers in the absence of symptoms.