Outcomes and variables
Clinical information was obtained from electronic medical reports. Epidemiological data, clinical details of COVID-19 infection, diagnostic tests, management and treatment were collected. Low educational level was considered when less than 8 years of studies had been completed. Co-morbidity was defined as the presence of preexisting hypertension, pre-existing diabetes, obesity (defined as body mass index ≥ 30 kg/m2), obstructive lung diseases or immunosuppression.
Maternal infection was classified as mild, moderate or severe. Moderate maternal infections were considered in cases of pneumonia confirmed by chest X-Ray, without presenting severity signs (basal oxygen saturation >90%; no need for vasopressors or ventilatory assistance). Maternal severe infections were defined when presented severe pneumonia, respiratory distress, sepsis or septic shock. Severe pneumonia criteria followed the American Thoracic Society and Infectious Diseases Society of America recommendations(15). Adult respiratory distress syndrome (ARDS) was considered in cases with suggestive clinical findings or radiological evidence of bilateral infiltrates plus oxygenation deficit (Sat O2/Fi O2ratio ≤315 or Pa O2/Fi O2 ratio ≤300). Sepsis was defined as life-threatening organ dysfunction caused by a dysregulated host response to infection, and septic shock as a subset of sepsis in which underlying circulatory and cellular/metabolic abnormalities are profound enough to substantially increase mortality, according to The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3) recommendations(16). Maternal worsening was considered when maternal transfer to intermediate or intensive care unit was needed for severe pneumonia, ARDS, sepsis or other major complications. Venous thrombosis or pulmonary thromboembolism were recorded as thrombotic complications. Cardiac complications included acute cardiac failure, arrythmias or ischemic disease.
Information about pregnancy and perinatal outcomes were obtained. Gestational age at delivery, mode of delivery, indication for delivery, neonatal weight, Apgar score, need of neonatal intensive care unit admission and neonatal SARS-CoV-2 infection were analyzed. When maternal conditions were favorable breastfeeding was allowed following the established protective measures. Neonatal SARS-CoV-2 nasopharyngeal PCR was obtained from all neonates within the first 48 hours.
Perinatal outcome results were compared with expected results from an historical cohort in the same institution.
The main outcome was the rate of vaginal delivery among COVID-19 pregnancies. Secondary outcomes were maternal or neonatal complications, and vertical transmission of SARS-CoV-2.