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Characteristics and Maternal and Birth Outcomes of Hospitalized Pregnant Women with Laboratory-Confirmed COVID-19 – COVID-NET, 13 States, March 1-August 22, 2020

Our take —

This descriptive study compared characteristics and outcomes among hospitalized pregnant women with COVID-19 with and without symptoms. The high proportion of asymptomatic cases suggests that, in many areas of the US, asymptomatic pregnant women are screened for COVID-19 prior to delivery and have good pregnancy outcomes. While the finding that pregnancy loss and preterm birth outcomes were more common among symptomatic compared to asymptomatic women adds to our knowledge and fits with previous disease severity data, the absolute levels and comparisons were not adjusted for other salient risk factors that may differ between groups. The sample size and geographic and racial/ethnic diversity suggests trends that can be further explored with prospective studies that measure how infection with SARS-CoV-2 impacts pregnancy outcomes in the United States.

Study design

Case Series, Cross-Sectional

Study population and setting

The authors used data from a population-based surveillance system of COVID-19-related hospitalizations in 14 states (COVID-NET), 13 of which were included in this study. The surveillance system includes all patients in the catchment area who tested positive for SARS-CoV-2 during or in the 14 days before hospitalization for any reason. This study sample was drawn from a subset (2,318 of 7,895 total records of women aged 15-49 years who were hospitalized with COVID-19) whose data was systematically abstracted from medical records by trained surveillance officers. Among this subset, 26% were pregnant. This study included 529 pregnant women, aged 15-49 years, with laboratory-confirmed SARS-CoV-2 who were hospitalized between March 1 and August 22, 2020.

Summary of Main Findings

The majority of pregnant women were aged 25-34 years, the majority (87%) were in their third trimester, Black and Hispanic women were overrepresented as compared to the catchment area (comprising 26.5% and 43% of the sample, respectively), and 20.6% had at least one other medical condition. Indication for hospitalization, recorded after June 1, 2020 (available for 54% of sample) found that hospitalizations in the first and second trimester were more likely due to COVID-19-related illness, while hospitalizations in the third trimester were more likely due to delivery and other obstetric needs. Slightly more than half (54.5%, n=326) did not have COVID-19 symptoms on admission. Among the 272 women with symptoms — most frequently fever and chills or cough — 16.2% required intensive care unit admission, 8.5% required mechanical ventilation, and 0.7% (2 women) died. Among hospitalizations that included pregnancy completion (458 of 598 hospitalizations), 10 (2.2%) resulted in pregnancy loss (5% of symptomatic women and 0.9% of asymptomatic women). Overall, 12.6% of live births were pre-term (23% among symptomatic and 8% among asymptomatic women).

Study Strengths

The key strength of this study is the population-based sampling frame, that while not designed to be representative of pregnant women specifically, nevertheless includes a racially/ethnically diverse sample of hospitalized pregnant women with COVID-19 from 13 US states. The data were abstracted by trained surveillance officers using systematic protocols, and the data was fairly complete with respect to race/ethnicity, comorbidities, and pregnancy outcomes during the hospitalization.

Limitations

Data from more than two-thirds of the hospitalized cases among women of reproductive age were not abstracted, and it is unclear how the included convenience sample may differ from the remainder of the records. Comparisons between the symptomatic and asymptomatic groups were unadjusted for key risk factors. Data on maternal and neonatal mortality were not collected beyond the initial hospitalization period, potentially undercounting deaths. The surveillance system does not enable the comparison of outcomes to those of pregnant women who were admitted to the same hospitals at the same time, but were not infected with SARS-CoV-2. Finally, this study does not provide information on birth outcomes among women who recovered from COVID-19 earlier in their pregnancies.

Value added

This study reported higher levels of preterm birth and pregnancy loss among women infected with SARS-CoV-2 with symptoms as compared to women who are asymptomatic, among a more representative sample than prior data from the US.

This review was posted on: 9 October 2020