This is the fourth birth cohort to be carried out in the city of Pelotas (Brazil) including more than 4 thousand children followed-up since the pre-natal period to study maternal-child health.

The Pelotas 2015 Birth cohort is the fourth birth cohort being established in Pelotas since 1982. Data is being collected with a focus on maintaining fidelity to the tools and instruments used in the previous cohorts with minimal adaptations when necessary. All children born in Pelotas during 2015 were included in the cohort, and the cohort has been followed four times, at birth, 3, 12 and 24 months (ongoing). In addition, an antenatal study identified and interviewed 73.8% of the mothers that subsequently delivered children that are now part of the cohort. The 4275 children included in the cohort are part of extensive assessments that include information on antenatal health and care, pregnancy health, gestational age, physical activity, sleep, health behaviours, socio-demographic characteristics, perinatal conditions, child anthropometry, delivery information, child mortality and morbidity, nutrition, growth, breastfeeding, neuro-cognitive development, access to health services, medicine use by both mother and child and genetic material. The cohort also nests 2 randomized clinical trials and a series of sub-studies. The data is starting to be analyzed and, among other findings, confirm the already alarming trends in surgical deliveries, amounting to 65.2% of all deliveries in 2015.

Inclusion Criteria:

• live births
• mothers living in urban area of the city
• delivered during 2015

Exclusion Criteria:

• stillbirths below 500g
• mothers living outside Pelotas

All live births from mothers living in Pelotas during the year 2015 were included in the birth cohort to be followed-up since birth.