Risk factors for oxygen requirement in hospitalized pregnant and postpartum women with COVID-19

ABSTRACT

Abstract Objective: To identify risk factors for Oxygen (O2) needs in pregnant and postpartum women with COVID-19. Methods: Prospective cohort involving pregnant women hospitalized with COVID-19 from April to October 2020. The oxygen need was analyzed regarding risk factors: demographic characteristics, clinical and laboratory parameters at hospital admission, and chest Computer Tomography (CT) findings. Poisson univariate analysis was used to estimate the Relative Risk (RR) and 95% Confidence Intervals. Results: 145 patients, 80 who used and 65 who did not use O2, were included. Body mass index ≥ 30, smoking, and chronic hypertension increased the risk of O2 need by 1.86 (95% CI 1.10-3.21), 1.57 (95% CI 1.16‒2.12), and 1.46 (95% CI 1.09‒1.95), respectively. Patients who were hospitalized for COVID-19 and for obstetric reasons had 8.24 (95% CI 2.8‒24.29) and 3.44 (95% CI 1.05‒11.31) times more use of O2 than those admitted for childbirth and abortion. Respiratory rate ≥ 24 breaths/min and O2 saturation < 95% presented RR for O2 requirements of 2.55 (1.82‒3.56) and 1.68 (95% CI 1.27-2.20), respectively. Ground Glass (GG) < 50% and with GG ≥ 50%, the risk of O2 use were respectively 3.41-fold and 5.33-fold higher than in patients who haven't viral pneumonia on CT. The combination of C-reactive protein ≥ 21 mg/L, hemoglobin < 11.0 g/dL, and lymphopenia < 1500 mm3 on hospital admission increased the risk of O2 use by 4.97-times. Conclusions: In obstetric patients, clinical history, laboratory, clinical and radiological parameters at admission were identified as a risk for O2 need, selecting the population with the greatest chance of worsening. HIGHLIGHTS In unvaccinated pregnant and postpartum women, any need for oxygen supply increases the risk of invasive ventilation. Obesity, smoking and chronic arterial hypertension proved to be risk factors for the use of oxygen in pregnant and postpartum women with COVID-19. The combination of C-reactive protein ≥ 21 mg/L, hemoglobin < 11.0 g/dL, and lymphopenia < 1500 mm on hospital admission and the presence of ground glass ≥ 50% in computer tomography increased the risk of O2 use by 4.97 and 5.33 times respectively in pregnant and postpartum women with COVID-19.