: Considering that the birth cohort study is the most appropriate model for studying and evaluating the relationship between exposures during the initial evolution and its long-term effects on the development of diseases, this prospective cohort study is designed for this purpose. Through a stratified random sampling, 6921 women, who were in the 20th to 30th week of gestation and lived in Fars province for at least six months prior to the interview, participated in this prospective cohort study. The study started in 2011 and the 4th follow up was finished in 2017. During the enrolment phase and four follow up after birth, the following information was collected in detail: socioeconomic status, knowledge and attitude of mother, husband toward normal vaginal delivery (NVD) and cesarean section (SC), early and late complications of delivery in mothers and babies, breastfeeding, any medical history in mothers and children, physical activity in children, and common psychiatric problems in mothers. So far, several articles have been published on the first results of the study. Mothers and children under the study will have three more follow ups until the children are 12 years old.