Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection During Pregnancy In China: A Retrospective Cohort Study

  1. Ming-Zhu Yin
  2. Li-juan Zhang
  3. Guang-Tong Deng
  4. Chao-Fei Han
  5. Min-Xue Shen
  6. Hong-Yin Sun
  7. Fu-Rong Zeng
  8. Wei Zhang
  9. Lan Chen
  10. Qing-Qing Luo
  11. Du-Juan Yao
  12. Min Wu
  13. Shi-Huan Yu
  14. Hui Chen
  15. David Baud
  16. Xiang Chen

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Abstract

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been identified as the cause of the ongoing worldwide epidemic of Coronavirus Disease 2019 (COVID-19) in China and worldwide. However, there were few studies about the effects of SARS-CoV-2 infection on pregnant women.

Methods

In this retrospective cohort study, we enrolled 31 pregnant women and 35 non-pregnant women from Jan 28 to Feb 28, 2020 to evaluate the effects of SARS-CoV-2 infection during pregnancy. Inflammatory indices were used to assess the severity of COVID-19. Evidence of vertical transmission was determined by laboratory confirmation of SARS-CoV-2 in amniotic fluid, placenta, neonatal throat and anal swab and breastmilk samples.

Findings

Compared with non-pregnant women, pregnant women had a significantly lower proportion of fever (54·8% vs. 87·5%, p = 0.006), a shorter average interval from onset to hospitalization (7·80 ±7·0d vs. 13·2 ± 8·2d, p = 0.005), and a higher proportion of severe or critical COVID-19 (32·3% vs. 11·4%, p =0.039). Neutrophil-to-lymphocyte ratio (NLR) and systematic immune-inflammation-based prognostic index (SII) were significantly higher on admission in severe/critical pneumonia group than moderate pneumonia group. We could not detect the presence of SARS-CoV-2 by RT-PCR in amniotic fluid, placenta, neonatal throat and anal swab and breastmilk samples.

Interpretation

The clinical symptoms of COVID-19 in pregnant women were insidious and atypical, compared with those in non-pregnant patients. SII and NLR could be a useful marker to evaluate the severity of COVID-19. There was no evidence of vertical transmission during pregnancy with SARS-CoV-2 infection.

Funding

National Natural Science Foundation of China and Research Funds for the Central Universities.

Research in context

Evidence before this study

We searched PubMed, Embase and Web of science for articles published up to March 1st, 2020, using the keywords (“novel coronavirus” OR “2019 novel coronavirus” OR “2019-nCoV” OR COVID-19 OR SARS-CoV-2) AND (pregnancy OR “maternal infection” OR “fetal infection”) AND “Cohort studies”.

We identified no published cohort studies on pregnant women with the 2019 novel coronavirus disease (COVID-19) infection.

Added value of this study

For this retrospective cohort study, we reviewed clinical records, laboratory findings, and chest CT scans from 31 pregnant women and 35 non-pregnant women from Jan 28 to Feb 28, 2020 to evaluate the effects of SARS-CoV-2 infection during pregnancy. Inflammatory indices were used to assess the severity of COVID-19. Evidence of vertical transmission was determined by laboratory confirmation of SARS-CoV-2 in amniotic fluid, placenta, neonatal throat and anal swab and breastmilk samples. Compared with non-pregnant women, pregnant women had a significantly lower proportion of fever (54·8% vs. 87·5%, p= 0.006), a shorter average interval from onset to hospitalization (7·80 ±7·0d vs. 13·2 ± 8·2d, p= 0.005), and a higher proportion of severe or critical COVID-19 (32·3% vs. 11·4%, p=0.039). Neutrophil-to-lymphocyte ratio (NLR) and systematic immune-inflammation-based prognostic index (SII) were significantly higher on admission in severe/critical pneumonia group than moderate pneumonia group. Amniotic fluid, placenta, neonatal throat and anal swab and breastmilk samples were tested for SARS-CoV-2 by RT-PCR and all results were negative.

Implications of all the available evidence

The clinical symptoms of COVID-19 in pregnant women were insidious and atypical, compared with those in non-pregnant patients. SII and NLR could be a useful marker to evaluate the severity of COVID-19. There was no evidence of vertical transmission during pregnancy with SARS-CoV-2 infection.

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  1. ScreenIT

    SciScore for 10.1101/2020.04.07.20053744: (What is this?)

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

    Table 1: Rigor

    Institutional Review Board StatementIRB: Ethical approval for the study was obtained from the Ethics Committee of Wuhan Union and Tongji hospitals of Huazhong University of Science and Technology, and written informed consent was waived by the Ethics Commission of the designated hospital for the emergency of COVID-19.
    Consent: Ethical approval for the study was obtained from the Ethics Committee of Wuhan Union and Tongji hospitals of Huazhong University of Science and Technology, and written informed consent was waived by the Ethics Commission of the designated hospital for the emergency of COVID-19.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.
    Sex as a biological variableStudy design and participants: For this retrospective cohort study, we included two cohorts of female inpatients (20-40 years old, female) from Jan 28 to Feb 28, 2020, at Wuhan Union and Tongji hospitals of Huazhong University of Science and Technology.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    All the analyses were performed with SPSS software, version 23.
    SPSS
    suggested: (SPSS, RRID:SCR_002865)

    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 study has several limitations. First, we only included the hospitalized patients with laboratory confirmed COVID-19. It could be more methodologically sound to include both pregnant outpatients and inpatients in the analysis to obtain a lees biased estimate comprehensive understanding of the effect of COVID-19 on pregnancy. Second, patient’s information such as pregnant outcomes in first and second trimester were incomplete and unavailable at the time of analysis. Third, selection bias might be introduced using 35 non-pregnant patients of reproductive age as control cohort. To clarify, we made a baseline comparison between these 35 non-pregnant patients and all female patients of reproductive age from Hunan province near Wuhan where COVID-19 broke out and found no difference (Table S2). Finally, considering the limited number in this study, we should treat the results with more caution. Non-significant P value still could not rule out the possibility of false negative results when comparing pregnant and non-pregnant patients. In summary, pregnant women with COVID-19 had insidious and atypical symptoms which increased the risk of misdiagnosis. SII and NLR could be useful markers to evaluate the severity of the COVID-19. There was no evidence of vertical transmission during pregnancy. These findings will be crucial to inform prophylactic and therapeutic strategies for pregnant women with COVID-19.

    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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  2. Version published to 10.1101/2020.04.07.20053744v1 on medRxiv