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

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 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 post-partum. 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, 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). 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.