Data collection
The current analysis used the JECS dataset released in June 2016
(dataset: jecs-ag-20160424). We used two types of data: (1) T1,
comprising data obtained from the self-reported questionnaires collected
during the first trimester (the first questionnaire), and included
questions related to the maternal medical background; (2) M0, which
included data for obstetric outcomes. These data were retrieved from the
medical records provided by each cooperating health care provider. The
participants with multiple-gestation pregnancies and those with missing
data were excluded from the analysis.