Figure 1. Participant Flow of the Population-Based Sample.

A, Entire cohort of children, including term (≥37 weeks 0 days’ gestation) and preterm-born (<37 weeks 0 days’ gestation) children. B, Cohort of term-born consecutive maternal sibling pairs.

^aTerm group included children born postterm at 42 weeks 0 days or more.

^bIn within-sibpair comparisons all maternal treatment exposure–discordant and nonexposure-concordant siblings are analyzed in consecutive order.