The incidence, characteristics and outcomes of pregnant women hospitalized with symptomatic and asymptomatic SARS-CoV-2 infection in the UK from March to September 2020: A national cohort study using the UK Obstetric Surveillance System (UKOSS)

  1. Nicola Vousden
  2. Kathryn Bunch
  3. Edward Morris
  4. Nigel Simpson
  5. Christopher Gale
  6. Patrick O’Brien
  7. Maria Quigley
  8. Peter Brocklehurst
  9. Jennifer J. Kurinczuk
  10. Marian Knight

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Abstract

There is a lack of population level data on risk factors, incidence and impact of SARS-CoV-2 infection in pregnant women and their babies. The primary aim of this study was to describe the incidence, characteristics and outcomes of hospitalized pregnant women with symptomatic and asymptomatic SARS-CoV-2 in the UK compared to pregnant women without SARS-CoV-2.

Methods and findings

We conducted a national, prospective cohort study of all hospitalized pregnant women with confirmed SARS-CoV-2 from 01/03/2020 to 31/08/2020 using the UK Obstetric Surveillance System. Incidence rates were estimated using national maternity data. Overall, 1148 hospitalized women had confirmed SARS-CoV-2 in pregnancy, 63% of which were symptomatic. The estimated incidence of hospitalization with symptomatic SARS-CoV-2 was 2.0 per 1000 maternities (95% CI 1.9–2.2) and for asymptomatic SARS-CoV-2 was 1.2 per 1000 maternities (95% CI 1.1–1.4). Compared to pregnant women without SARS-CoV-2, women hospitalized with symptomatic SARS-CoV-2 were more likely to be overweight or obese (adjusted OR 1.86, (95% CI 1.39–2.48) and aOR 2.07 (1.53–2.29)), to be of Black, Asian or Other minority ethnic group (aOR 6.24, (3.93–9.90), aOR 4.36, (3.19–5.95) and aOR 12.95, (4.93–34.01)), and to have a relevant medical comorbidity (aOR 1.83 (1.32–2.54)). Hospitalized pregnant women with symptomatic SARS-CoV-2 were more likely to be admitted to intensive care (aOR 57.67, (7.80–426.70)) but the absolute risk of poor outcomes was low. Cesarean births and neonatal unit admission were increased regardless of symptom status (symptomatic aOR 2.60, (1.97–3.42) and aOR 3.08, (1.99–4.77); asymptomatic aOR 2.02, (1.52–2.70) and aOR 1.84, (1.12–3.03)). The risks of stillbirth or neonatal death were not significantly increased, regardless of symptom status.

Conclusions

We have identified factors that increase the risk of symptomatic and asymptomatic SARS-CoV-2 in pregnancy. Clinicians can be reassured that the majority of women do not experience severe complications of SARS-CoV-2 in pregnancy.

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  1. Version published to 10.1371/journal.pone.0251123
  2. ScreenIT

    SciScore for 10.1101/2021.01.04.21249195: (What is this?)

    Please note, not all rigor criteria are appropriate for all manuscripts.

    Table 1: Rigor

    Institutional Review Board Statementnot detected.
    Randomizationnot detected.
    Blindingnot detected.
    Power AnalysisIn this national observational study, the study sample size was governed by the disease incidence, thus no formal power calculation was carried out.
    Sex as a biological variableAll 194 hospitals in the UK with a consultant-led maternity unit participate, and thus the mechanism to collect comprehensive information about women hospitalized with SARS-CoV-2 in pregnancy was already in place at the start of the pandemic.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    Statistical methods and analysis: Statistical analyses were performed using STATA version 15 (Statacorp, TX, USA).
    STATA
    suggested: (Stata, RRID:SCR_012763)
    Statacorp
    suggested: None

    Results from OddPub: We did not detect open data. We also did not detect open code. Researchers are encouraged to share open data when possible (see Nature blog).

    Results from LimitationRecognizer: We detected the following sentences addressing limitations in the study:
    However, it is a limitation that despite national guidance, practice around initiation of universal screening will have varied between hospitals depending on testing capacity with some initiating screening earlier or later than recommended. This will have influenced the proportion of asymptomatic women detected throughout this study. We have confirmed that pregnant women hospitalized with SARS-CoV-2 were more likely to be Black, Asian or Other minority ethnicity, irrespective of symptom status, age, BMI and medical comorbidities. In the non-pregnant population, a recent systematic review has demonstrated that Black and Asian ethnic groups are more likely to be infected with SARS-CoV-2 compared to those of White ethnicity [16]. This suggests that the disproportionate impact could be attributable to increased infection in these ethnic groups. However, disparities in maternal mortality between ethnic groups are well known [12] and likely a result of complex interrelated factors, which may also be important in explaining the increased risk of SARS-CoV-2. For example, individuals from ethnic minority backgrounds are more likely to live in larger household sizes[17], be of lower socioeconomic status [18], be employed as a public-facing key worker or less able to work from home [19]. Further research is required to determine the reasons for this disparity in the risk of hospitalization with SARS-CoV-2 and how to mitigate the risk through the care we provide. Women at increased risk ...

    Results from TrialIdentifier: No clinical trial numbers were referenced.

    Results from Barzooka: We did not find any issues relating to the usage of bar graphs.

    Results from JetFighter: We did not find any issues relating to colormaps.

    Results from rtransparent:
    • Thank you for including a conflict of interest statement. Authors are encouraged to include this statement when submitting to a journal.
    • Thank you for including a funding statement. Authors are encouraged to include this statement when submitting to a journal.
    • No protocol registration statement was detected.

    About SciScore

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  3. Version published to 10.1101/2021.01.04.21249195v1 on medRxiv