In December 2019, SARS-CoV-2 infection emerged and spread rapidly across the world. On January 30, 2020, coronavirus disease (COVID-19) was declared a public health emergency by the WHO and on March 11, 2020, a pandemic was declared [1]. Although the infection appeared flu-like in most of the population [2], groups of vulnerable patients were identified, including but not limited to older patients, those with obesity, with respiratory disease or ongoing immunosuppression; all appeared more prone to develop severe respiratory disease with possibly fatal acute respiratory distress syndrome (ARDS) [3]. Obstetric care institutions worldwide rapidly queried if pregnant women might be more likely to develop ARDS, as previously demonstrated for other respiratory viruses, such as Influenza virus and other coronaviruses, such as Middle East respiratory syndrome-Coronavirus (MERS-CoV) [4], [5], [6]. Questions about the possible association between COVID-19 during pregnancy and poor perinatal outcomes arose simultaneously.

The first publications on COVID-19 during pregnancy were case series that suggested a higher risk of morbidity in pregnant than nonpregnant women of the same age [7], [8], [9]. Subsequent observational studies based on varied sampling frames and testing strategies reported perinatal outcomes in pregnant women [10], [11], [12], [13]. Several series reported obstetric complications among pregnant women hospitalized for COVID. These data, because they focused on women with the most severe presentations or with specific immunosuppression, were likely to overestimate the risks associated with the infection at a global level [14,15]. Reviews reported perinatal outcomes that implied a higher risk of preterm birth, preeclampsia, in utero fetal death, and postpartum hemorrhage [16,17]. It has not yet been possible to determine whether they might be a direct effect of the virus or rather of the epidemic's impact on health care systems.

To date, population-based studies, most of which collected data from registers of women hospitalized during pregnancy for COVID-19, remain sparse [18]. The impact of COVID-19 on perinatal care and obstetric management is thus difficult to evaluate.

Here, we included questions about COVID-19 in a French nationwide population-based study to evaluate its prevalence and determinants during pregnancy. Our secondary objective was to assess obstetric practices and perinatal outcomes for pregnant women with this disease.