RA-COVID-19 V16 - Recherche - Action Coronavirus disease 2019 - Vague 16

COVID19 and PERINATal health: improving knowledge and tools to protect pregnant women and newborns during infectious disease epidemics – COV_PERINAT

COVID19 and PERINATal health: improving knowledge and tools to protect pregnant women and newborns during infectious disease epidemics

Pregnant women and newborns are vulnerable populations during a pandemic because of the risks related to infection, but also because of indirect effects related to the pandemic and societal mitigation measures. Pathways include restricted healthcare access as well as the consequences of economic hardship and anxiety and stress. This study aims to study the indirect effects of the pandemic on perinatal health using the medico-administrative databases of the National System of Health Data (SNDS).

Pregnant women and children, vulnerable populations during a pandemic

Pregnant women and children constitute vulnerable populations during a pandemic. This is because of the specificity of their immune systems and the possibility of mother to child transmission, their non-deferrable needs for health services and the effects of environmental factors on pregnancy outcomes, notably the strong association of social disadvantage with risks of perinatal morbidity and mortality. Because pregnant women and newborns are generally in good health and because health care organization and the socioeconomic context have a strong influence on their outcomes, research studies require large population-based samples which rely on routine data sources. This study aims to investigate population measures of health and care of pregnant women and newborns associated with the pandemic and societal mitigation strategies using the French National Health Data System (SNDS). Secondary objectives are to evaluate use of these routine data for pandemic evaluations and to contribute to on-going French and European studies on COVID-19 and perinatal health.

After preliminary analyses using delivery hospitalizations between 2016 and 2020 (>3M births), we created a cohort of delivery (mother) and birth (newborn) hospitalizations over the same period; the database was later extended to 2021 to capture conceptions in 2020. Principal outcomes are: terminations of pregnancy, stillbirth, singleton live preterm birth and cesarean delivery. We examined differences in rates over time to identify pandemic-related effects using graphical presentations, period comparisons, autoregressive integrated moving average (ARIMA) and other time series models. We identified relevant periods and geographic zones in 2020 to structure the analysis plan.

A first study on perinatal health outcomes during the strict nationwide lockdown in France found that preterm birth rates were 6% (OR: 0.94, 95%CI: 0.90-0.98) lower than expected over this period, while cesarean and stillbirth rates were stable. Larger differences were observed in districts with low (OR: 0.92, 95%CI 0.87-0.98) versus moderate/high COVID-19 incidence (OR: 0.97, 95%CI 0.92-1.03). The results of this study were published in the Annals of Epidemiology. Subsequent analyses investigated patterns over time in 2020 finding that preterm birth rates returned to expected levels in the summer of 2020. In September and October, there was a decrease of similar magnitude to the first lockdown (OR: 0.93 (95%CI: 0.88-0.97)), but not during the second lockdown (OR: 0.97 (95%CI: 0.91-1.04)). No detectable differences were seen for cesarean delivery and stillbirth, except for a slightly higher cesarean delivery rate in the fifth period. On-going analyses on conception cohorts seek to assess whether the population composition or pregnancy exposure to the first lockdown explain these results.

At the onset of this project, there were concerns that perinatal outcomes would be adversely affected by the pandemic and lockdown measures. Reassuringly, we did not document a worsening of population indicators of perinatal health in France in 2020. Instead, our study documented a paradoxical decline in preterm birth rates. This result, noted in some, but not all, studies across multiple contexts, is one of the more puzzling outcomes of the pandemic and propelled research to confirm and to explain it. The strict, time-delineated lockdown and large number of births in France provides a unique context for illustrating the existence and temporal pattern of this effect. Our research comparing modeling approaches also showed the likelihood of spurious outcome in the published literature on this topic. On-going work on conception cohorts to deconstruct period versus cohort effects takes this research beyond the current state of the art. A close collaboration with the European PHIRI project made it possible to place French results in a European context and to inform the methods and analytic framework of the European study, with several publications in preparation. More broadly, our project highlighted the value of interrupted time series approaches in perinatal health, leading to new investment within our team as well as projects to improve the validity of routine maternal and health indicators in the SNDS, vital for this research.

Fresson J, Bruckner TA, Ray CL, Goffinet F, Rey S, Blondel B, Deneux-Tharaux C, Ancel PY, Zeitlin J. Decreases in preterm birth during the first COVID-19 lockdown in France by gestational age sub-groups and regional COVID-19 incidence. Annals of epidemiology. 2022;72:74-81.

Pregnant women and children constitute vulnerable populations during a pandemic. This is because of the specificity of their immune systems and the possibility of mother to child transmission, their non-deferrable needs for health services and the effects of environmental factors on adverse pregnancy outcomes, notably the strong association of social disadvantage with risks of perinatal morbidity and mortality. Furthermore, adverse perinatal events can have lifelong consequences. Mortality and morbidity resulting from infection are directly related to the pandemic, while indirect effects can stem from reductions in the accessibility or quality of health services or from mitigation policies and economic hardship. Because pregnant women and newborns are generally in good health and because many of these health consequences may depend on health care organization and the socioeconomic context, studies of these effects require large population-based samples.
The COV-PERINAT study’s aim is to investigate the indirect effects of the pandemic on the health of pregnant woman and newborns using routine hospital and administrative databases in the French National Health Data System (SNDS). It complements an on-going population-based study on the direct effects of the infection on the health of pregnant women and their newborns in France (COROPREG). Specifically, this project will (1) evaluate changes in population measures of health and healthcare use among pregnant women and newborns associated with the pandemic and strategies to contain the pandemic, (2) investigate whether these consequences differ by healthcare organization, socioeconomic context and other environmental factors, (3) assess the strengths and the weaknesses of using these routine sources to evaluate the impact of the pandemic and generate knowledge to reinforce monitoring capacity for future outbreaks, and (4) contribute to other on-going and future studies that rely on these data sources, including the COROPREG study and a European study (PHIRI) to facilitate exchange of population data between European countries.
Requested funding for the 12 month study period will cover the costs of an experienced statistician to work with perinatal health researchers to (1) establish a validated cohort of pregnant women and their newborns (births from January 2016 to December 2020) linked to contextual data about the pandemic, pandemic policies and area-based organizational, social and environmental factors, (2) describe and analyze changes in population measures of maternal and newborn health, taking into consideration seasonality using time series models, and (3) assess the influence of context on these changes. The team has extensive experience analyzing population data on perinatal health. A scientific committee will involve experts from professional societies and public health agencies in the interpretation and dissemination of the results. Complementarity with on-going projects and possibilities for new follow-up projects ensure that the results produced within the 12 month period will reinforce the foundation for further research on COVID-19 among pregnant women and newborns.

Project coordination

Jennifer ZEITLIN (Centre de Recherche en Epidémiologie et StatistiqueS)

The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.

Partner

CRESS Centre de Recherche en Epidémiologie et StatistiqueS

Help of the ANR 60,816 euros
Beginning and duration of the scientific project: March 2021 - 12 Months

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