Outcomes and proportions of pregnant women during the first and consecutive waves of coronavirus disease 2019: observational cohort study

OBJECTIVES: It has been suggested that pregnant women were affected more severely during the late wave, as opposed to the early wave of the coronavirus disease 2019 (COVID-19) pandemic. The aim of our study was to compare the proportion of pregnant women among hospitalized women of childbearing age, their rate of intensive care (ICU) admission, need for mechanical ventilation and mortality during the waves. METHODS: The study is a retrospective analysis of claims data on women of childbearing age (16–49 years) admitted to 76 hospitals with a laboratory-confirmed severe acute respiratory syndrome coronavirus 2 infection. The observation period was divided into first wave (7 March 2020 to 30 September 2020) and second wave (1 October to 17 April 2021). Co-morbidities derived from claims data were summarized in the Elixhauser Co-morbidity Index (ECI). RESULTS: A total of 1879 women were included, 532 of whom were pregnant. During the second wave, the proportion of pregnant women was higher (29.3% (484/1650) versus 21.0% (48/229), p < 0.01). They were older (mean ± SD 29.1 ± 5.9 years versus 27 ± 6.3 years, p 0.02 in the first wave) and had comparable co-morbidities (ECI mean ± SD 0.3 ± 3.5 versus –0.2 ± 2.0, p 0.30). Of the pregnant women, 6.2% (3/48) were admitted to ICU during the first wave versus 3.3% (16/484) during the second wave (OR 0.51, 95% CI 0.14–1.83, p 0.30), 2.1% (1/48) were ventilated versus 1.2% (6/484, OR 0.60, 95% CI 0.07–5.23, p 0.64). No deaths were observed among the hospitalized pregnant women in either wave. CONCLUSIONS: Proportionally more pregnant women with COVID-19 were hospitalized in the second wave compared with the first wave but no more severe outcomes were registered.