Characteristics and outcomes of pregnant women admitted to hospital with confirmed SARS-CoV-2 infection in UK: national population based cohort study

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

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Abstract

Objectives

To describe a national cohort of pregnant women admitted to hospital with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in the UK, identify factors associated with infection, and describe outcomes, including transmission of infection, for mothers and infants.

Design

Prospective national population based cohort study using the UK Obstetric Surveillance System (UKOSS).

Setting

All 194 obstetric units in the UK.

Participants

427 pregnant women admitted to hospital with confirmed SARS-CoV-2 infection between 1 March 2020 and 14 April 2020.

Main outcome measures

Incidence of maternal hospital admission and infant infection. Rates of maternal death, level 3 critical care unit admission, fetal loss, caesarean birth, preterm birth, stillbirth, early neonatal death, and neonatal unit admission.

Results

The estimated incidence of admission to hospital with confirmed SARS-CoV-2 infection in pregnancy was 4.9 (95% confidence interval 4.5 to 5.4) per 1000 maternities. 233 (56%) pregnant women admitted to hospital with SARS-CoV-2 infection in pregnancy were from black or other ethnic minority groups, 281 (69%) were overweight or obese, 175 (41%) were aged 35 or over, and 145 (34%) had pre-existing comorbidities. 266 (62%) women gave birth or had a pregnancy loss; 196 (73%) gave birth at term. Forty one (10%) women admitted to hospital needed respiratory support, and five (1%) women died. Twelve (5%) of 265 infants tested positive for SARS-CoV-2 RNA, six of them within the first 12 hours after birth.

Conclusions

Most pregnant women admitted to hospital with SARS-CoV-2 infection were in the late second or third trimester, supporting guidance for continued social distancing measures in later pregnancy. Most had good outcomes, and transmission of SARS-CoV-2 to infants was uncommon. The high proportion of women from black or minority ethnic groups admitted with infection needs urgent investigation and explanation.

Study registration

ISRCTN 40092247.

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  1. ScreenIT

    SciScore for 10.1101/2020.05.08.20089268: (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 AnalysisData on maternal and perinatal deaths were cross-checked with data from the MBRRACE-UK collaboration, the organisation responsible for maternal and perinatal death surveillance in the UK. 27 Sample size: In 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 variableNominated reporting clinicians were asked to notify all pregnant women with confirmed SARS-CoV-2 admitted to their hospital, using a live reporting link specific to each individual reporter.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    Statistical tabulation and analyses were performed using STATA version 15 (KB/MK).
    STATA
    suggested: (Stata, RRID:SCR_012763)

    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:
    This rapid report has been produced at a time when active transmission of SARS-CoV-2 is still occurring, with around 100 pregnant women hospitalised in the UK with infection each week, and the limitations of these data must therefore be recognised. We do not yet have complete pregnancy outcomes for women who were admitted but subsequently discharged well, and a number of women were still inpatients at the time of writing. The data collected for this rapid national cohort study were restricted to essential items, therefore we do not have daily indicators of women’s clinical condition, blood and other test results. Nevertheless, these results do show the benefits of systems such as UKOSS which can be rapidly activated to undertake comprehensive studies such as this in a public health emergency. UKOSS studies were activated for influenza A/H1N1 33 and Zika virus34 in pregnancy; countries in the International Network of Obstetric Survey Systems (INOSS) 35 are also undertaking similar national studies to allow for the unification of population-based data across multiple countries and avoiding the biases of data collected through centre-based registries. The National Institute for Health Research’s Clinical Research Network, 36 with midwifery and obstetric leads coordinating networks of research staff, also help ensure rapid and accurate collection of these valuable data even in the context of the pressurised health system in a pandemic. The addition of these national, population-b...

    Results from TrialIdentifier: We found the following clinical trial numbers in your paper:

    IdentifierStatusTitle
    ISRCTN40092247NANA

    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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  2. Version published to 10.1136/bmj.m2107
  3. Version published to 10.1101/2020.05.08.20089268v1 on medRxiv