Spatiotemporal Characteristics and Risk Factors for All andSeverity-Specific Preterm Births in Southern China, 2014-2021:Large Population-Based Study

Background: The worldwide incidence of preterm births is increasing, and the risks of adverse outcomes for preterm infantssignificantly increase with shorter gestation, resulting in a substantial socioeconomic burden. Limited epidemiological studieshave been conducted in China regarding the incidence and spatiotemporal trends of preterm births. Seasonal variations in riskindicate the presence of possible modifiable factors. Gender influences the risk of preterm birth. Objective: This study aims to assess the incidence rates of preterm birth, very preterm birth, and extremely preterm birth;elucidate their spatiotemporal distribution; and investigate the risk factors associated with preterm birth.Methods: We obtained data from the Guangdong Provincial Maternal and Child Health Information System, spanning fromJanuary 1, 2014, to December 31, 2021, pertaining to neonates with gestational ages ranging from 24 weeks to 42 weeks. Theprimary outcome measures assessed variations in the rates of different preterm birth subtypes over the course of the study, suchas by year, region, and season. Furthermore, we examined the relationship between preterm birth incidence and per capita grossdomestic product (GDP), simultaneously analyzing the contributing risk factors. Results: The analysis incorporated data from 13,256,743 live births. We identified 754,268 preterm infants and 12,502,475full-term infants. The incidences of preterm birth, very preterm birth, and extremely preterm birth were 5.69 per 100 births, 4.46per 1000 births, and 4.83 per 10,000 births, respectively. The overall incidence of preterm birth increased from 5.12% in 2014to 6.38% in 2021. The incidence of extremely preterm birth increased from 4.10 per 10,000 births in 2014 to 8.09 per 10,000births in 2021. There was a positive correlation between the incidence of preterm infants and GDP per capita. In more developedeconomic regions, the incidence of preterm births was higher. Furthermore, adjusted odds ratios revealed that advanced maternalage, multiple pregnancies, and male infants were associated with an increased risk of preterm birth, whereas childbirth in theautumn season was associated with a protective effect against preterm birth. Conclusions: The incidence of preterm birth in southern China exhibited an upward trend, closely linked to enhancements inthe care capabilities for high-risk pregnant women and critically ill newborns. With the recent relaxation of China's 3-child policy,coupled with a temporary surge in advanced maternal age and multiple pregnancies, the risk of preterm birth has risen. Consequently,there is a pressing need to augment public health investments aimed at mitigating the risk factors associated with preterm birth,thereby alleviating the socioeconomic burden it imposes