Preterm labor (PL) is the leading cause of hospitalization during pregnancy and premature birth the leading cause of fetal morbidity and mortality in France. PL is defined by regular and painful uterine contractions associated with a change in the cervix, between 22 and 36 weeks of gestation.

It has been shown that the risk of spontaneous prematurity increases particularly in case of working over 40 hours per week, hard physically conditions, or prolonged daily transport time. Rest is one of the most efficient measure to prevent PL and should be proposed to all pregnant women, and combined with other therapies such as tocolysis or cerclage when needed.

The very particular period of lockdown during the COVID-19 pandemic had pregnant women to drastically reduce their activity. They suspended their work and stayed home for various reasons such as pregnancy in progress, children at home, and also collective reasons such as teleworking or workplace closure.

During the lockdown period from March 17th to May 11th 2020, fewer preterm labor and less spontaneous prematurity have been suspected by the neonatology and obstetrics teams throughout the Lorraine region.

Our study aims to objectively confirm this observation. In this investigation we aim to find a relationship between lockdown, PL and spontaneous prematurity which would need to re-evaluate public health recommendations for pregnant women outside the lockdown.

Inclusion Criteria:

• Any prematurely born infant before 37 SA and care for by the level III NICU, over the predefined periods.

Exclusion Criteria:

• non premature newborn

All premature newborns born before 37 SA and care for by the level III NICU of the Maternité Régionale Universitaire de Nancy, over time periods from March 1 to June 1 of the years 2015 to 2020.