Fig. 2

Flowchart Showing the Composition of the Derivation, Temoral- and External-Validation Cohorts. This image presents a schematic outline of the selection of the study cohorts. Each case in the study is depicted by a sequence of symbols: a circle (●) for the initial or index pregnancy and a diamond (◆) for the subsequent pregnancy. The derivation cohort comprised cases from 12 primary facilities and 2 tertiary centers with subsequent pregnancies that resulted in deliveries between 2009 and 2019, represented by blue lines. The temporal-validation cohort consisted of cases exclusively from 2 tertiary centers with subsequent pregnancies delivered between 2020 and 2024, as shown by the red lines. The external-validation cohort consisted of cases from another tertiary center with subsequent pregnancies that resulted in deliveries between 2017 and 2023, as shown by the yellow lines. BMI body mass index