The Environment, Mother and Child Cohort study, initiated in September 2012, is an ongoing population-based birth cohort involving pregnant women from Jerusalem and its surroundings. The study recruited healthy women with spontaneous, singleton pregnancies before 18 weeks of gestation, with an average recruitment gestational age of 13.7 weeks. The mean maternal age was 32.2 years, and the majority of pregnant women gave birth to boys. Participants included women who intended to give birth at one of the Hadassah Medical Center campuses, and their children during the follow-up.