Increasing Prevalence and Temporal Trend of Prematurity, São Paulo, Brazil, 2000–2023

Background: premature birth is a significant public health problem, especially in developing countries such as Brazil. Premature newborns require special care from birth, often requiring prolonged hospitalization and continuous monitoring by various specialists after discharge. Infant Mortality among children under five years of age in Brazil is alarming, with prematurity being the main cause of death in this age group. Objectives: we aim to analyze the prevalence and temporal trend of premature live births in the state of São Paulo, Brazil, in the period 2000–2023. Methods: this is an Ecological, Time-Series Study with secondary data on premature live births in the state of São Paulo, Brazil, from 2000 to 2023. The variables in this study are aggregated measures by year. The Annual Percentage Change and the Average Annual Percentage Change in the percentage of premature live births were estimated by Joinpoint regression. Results: the percentage of premature live births in the period 2000 to 2023 was 9.71%. The average annual percentage change showed an increase of 2.30% per year. In the 2010 to 2013 segment, there was an increase of 12.58% per year (p ≤ 0.05), with subsequent stability in the 2013 to 2016 segment (p ≥ 0.05). The largest annual increases occurred in the number of 4 to 6 prenatal consultations and cesarean sections, with an annual percentage change of 4.51% per year and 2.68% per year, respectively. In the birth weight category equal to or greater than 2500 g, there was an increase in premature live births of 2.50% per year. All categories of the variables sex, type of pregnancy, and type of delivery increased in the period 2000–2023 (p ≤ 0.05). Conclusions: given the increase in the prematurity rate in the period 2000–2023, a long-term growing trend is expected in the largest and most developed state in Brazil.