COVID-19 pandemic impact on preterm birth and stillbirth rates associated with socioeconomic disparities: A quasi-experimental study

  1. Laila Aboulatta
  2. Kaarina Kowalec
  3. Christine Leong
  4. Joseph Delaney
  5. Jamie Falk
  6. Silvia Alessi-Severini
  7. Dan Chateau
  8. Qier Tan
  9. Katherine Kearns
  10. Christina Raimondi
  11. Alekhya Lavu
  12. Lara Haidar
  13. Christine Vaccaro
  14. Sherif Eltonsy

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Abstract

Background

Conflicting evidence exists on the impact of the COVID-19 pandemic restrictions on preterm birth (PTB) and stillbirth rates. We aimed to evaluate changes in PTB and stillbirth rates before and during the pandemic period and assess the potential effect modification of socioeconomic status (SES).

Methods

Using the linked administrative health databases from Manitoba, Canada, we conducted a quasi-experimental study among all pregnant women, comparing 3.5 years pre-pandemic (1 October 2016 to 29 February 2020) to the first year of the pandemic (1 March 2020 to 31 March 2021). We used interrupted time series analysis using autoregressive integrated moving average models to assess the quarterly rates of PTB (<37 weeks) and stillbirths. We calculated the predicted trends based on pre-pandemic period data. Finally, we evaluated the lower and higher SES (average annual household income) using subgroup analysis and interaction models.

Results

We examined 70,931 pregnancies in Manitoba during the study period. Following the implementation of COVID-19 restrictions in March 2020, there were no statistically significant changes in the rates of both PTB (p=0.094) and stillbirths (p=0.958). However, over the pandemic, the PTB rate significantly decreased as a rebound effect by 0.63% per quarter(p=0.005); whereas the stillbirth rate did not change significantly (p=0.878) compared to pre-pandemic period. During the first quarter of 2021, the absolute differences in the observed and expected PTB and stillbirth percentages were 2.05% and 0.04%, respectively. We observed a statistically significant effect modification by SES for PTB rates (p=0.047).

Conclusion

While the onset of COVID-19 pandemic restrictions was not associated with significant effects on PTB and stillbirth rates, we observed a statistically significant rebound effect on PTB rates. The impact of COVID-19 on preterm birth was dependent on SES, with higher influence on families with lower SES. Further studies are needed to detect future trend changes during pandemic waves after 2021 and assess potential underlying mechanisms.

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  1. ScreenIT

    SciScore for 10.1101/2022.05.25.22275592: (What is this?)

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

    Table 1: Rigor

    Ethicsnot detected.
    Sex as a biological variable35 Exposure and Outcomes: Pregnant women exposed to the pandemic restrictions during the first and second waves between March 1, 2020, and March 31, 2021, were compared to those who were pregnant before the pandemic period.
    Randomizationnot detected.
    Blindingnot detected.
    Power Analysisnot detected.

    Table 2: Resources

    Software and Algorithms
    SentencesResources
    42 Analyses were conducted using SAS, version 9.4 (SAS Institute, Inc)
    SAS
    suggested: (SASqPCR, RRID:SCR_003056)
    SAS Institute
    suggested: (Statistical Analysis System, RRID:SCR_008567)

    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:
    The main limitations of this study should be acknowledged. We did not examine the influence of COVID-19 infection on the study outcomes; however, the number of reported COVID-19 positive pregnant women was small in relation to the total pregnancies in our cohort, and it is unlikely that viral infection would change our results.43 Although, we did not investigate variations across the different regions of Manitoba, the changes to maternal healthcare were implemented across the provincial healthcare system minimizing any differential variability within the data. However, some rural regions may have been substantially impacted during the pandemic compared to larger cities. Moreover, we did not include out of hospital births, maternal smoking and alcohol/substance use, and vaccination rates among pregnant women in Manitoba

    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.

    Results from scite Reference Check: We found no unreliable references.

    About SciScore

    SciScore is an automated tool that is designed to assist expert reviewers by finding and presenting formulaic information scattered throughout a paper in a standard, easy to digest format. SciScore checks for the presence and correctness of RRIDs (research resource identifiers), and for rigor criteria such as sex and investigator blinding. For details on the theoretical underpinning of rigor criteria and the tools shown here, including references cited, please follow this link.

  2. Version published to 10.1101/2022.05.25.22275592v1 on medRxiv