The association between COVID-19 and preterm delivery: A cohort study with a multivariate analysis

SPANISH OBSTETRIC EMERGENCY GROUP,; Martinez Perez, O.; Prats Rodriguez, P.; Muner Hernandez, M.; Encinas Pardilla, M. B.; Perez Perez, N.; Vila Hernandez, M. R.; Villalba Yarza, A.; Nieto Velasco, O.; Del Barrio Fernandez, P. G.; Forcen Acebal, L.; Orizales Lago, C. M.; Martinez Varea, A.; Munoz Abellana, B.; Suarez Arana, M.; Gonzalez Seoane, R.; Martinez Diago, C.; Canedo Carballeira, E.; Alferez Alvarez Mallo, M.; Casanova Pedraz, C.; Alomar Mateu, O.; Lesmes Heredia, C.; Wizner de Alva, J. C.; Bernardo Vega, R.; Macia Badia, M.; Alvarez Colomo, C.; Sanchez Munoz, A.; Alicart, Pratcorona

Structured abstract Objective: 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. Design and setting: Throughout Spain, 45 hospitals took part in the universal screening of pregnant women going into labour using polymerase chain reaction (PCR) for COVID 19 since late March 2020. Methods: The cohort of exposed and unexposed pregnancies was followed up until 6 weeks postpartum. Multivariate logistic regression analysis, adjusting for known confounding variables, determined the adjusted odds ratio (aOR) with 95% confidence intervals (95% CI) of the association of COVID 19 exposure, compared to non exposure, with infection related obstetric outcomes. Main outcome measures: Preterm delivery (primary), premature rupture of membranes and neonatal intensive care unit admissions. Results: In the cohort of 1,009 screened pregnancies, 246 were COVID 19 positive. Compared to non exposure, COVID 19 exposure 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), premature rupture of membranes at term (39 vs 75, % 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). Conclusion: This first prospective cohort 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.