Preplanned Studies: Trends in the Incidence of High-Risk Newborns Based on a New Conceptual Framework — Beijing Municipality, China, 2013–2022

This study is the first to apply a new conceptual framework to evaluate the incidence of high-risk newborns in Beijing. Data from the Beijing Maternal and Children Information System indicate an overall SVN incidence of 9.94% over the past decade. The system also reveals incidences of 4.51% for SGA, 4.80% for LBW, and 6.35% for preterm births over the same period. Using any subtype of SVN to assess the number of high-risk newborns would lead to an underestimation of 40%–50%, a finding similar to a Brazilian study (2). The new definition encompasses SGA, LBW, and preterm birth under the umbrella term SVN. In this study, routine individual-level data collection in midwifery hospitals allows for accurate assessment of the burden associated with being born small or preterm. Because these three definitions are not mutually exclusive, a new SVN classification method is used: term-SGA, preterm-SGA, and preterm-non-SGA. Although this new classification covered 95.43% (88,355/92,586) of LBW babies in our study, slightly lower than in previous studies (1), public health practitioners are advised to use SVN when assessing the number of high-risk newborns. This recommendation is based on the new conceptual framework’s ability to better estimate the total burden of high-risk newborns.

The incidence of SVNs in this study was markedly lower than the 26.2% reported for 195 countries and areas in 2020. The global study indicated that of all SVNs, 1.1% were preterm-SGA, 8.8% were preterm-nonSGA, and 16.3% were term-SGA (3). Over the past ten years in Beijing, the incidences of SVNs (9.94%), preterm-nonSGA (5.42%), and term-SGA (3.58%) were significantly lower than global data, while the incidence of preterm-SGA (0.93%) was slightly lower. While few studies have used this new conceptual framework, previous research has shown that the incidences of preterm birth, LBW, and SGA vary significantly between countries (4–6). Similarly, preterm birth incidence varies by region within China (7). Regional differences in economic development, maternal demographic characteristics, and antenatal care capabilities should be considered when comparing SVN incidence.

The incidence of term-SGA decreased from 4.60% in 2013 to 3.51% in 2022 (linear regression, t=−2.582, P=0.033). This decrease may be partially attributed to Beijing’s status as one of the most economically developed areas in China, with a higher level of antenatal care compared to most other areas. Increasing the quantity and quality of antenatal contact with healthcare providers can reduce or prevent the birth of SVN (8). The Chinese government’s implementation of the Basic Public Health Service project in 2009, which included establishing annual maternal health records and prenatal examinations, can further improve maternal health services and reduce maternal mortality (9). Furthermore, an analysis of maternal and child healthcare quality in 31 Chinese provincial-level administrative divisions (PLADs) from 2010 to 2020, using 6 indicators (maternal mortality rate, maternal health record establishment rate, pregnancy systematic management rate, prenatal examination rate, postpartum visit rate, and hospital delivery rate), ranked Beijing among the top areas for maternal and child health quality (10). Despite the decrease in term-SGA incidence, this condition remains a concern as it accounted for 26.4% of SVN-associated neonatal deaths (1).

Despite some progress, a significant health concern remains. This study found no decrease in the incidence of SVN, with preterm-SGA and preterm-nonSGA births increasing over the past 10 years. This suggests a need for improved interventions, particularly those targeting preterm infants. Our study found a strong association between multiple pregnancies and preterm birth (preterm-SGA: aOR=32.75, 95% CI: 31.70, 33.84; preterm-nonSGA: aOR=17.15, 95% CI: 16.83, 17.48). Interventions aimed at reducing SVN should prioritize women of advanced maternal age, primiparous women, and those with multiple pregnancies.

This study is among the first to group preterm birth, SGA, and LBW together under the umbrella term SVN. This study has several additional strengths. First, the Maternal and Children Information System in Beijing collects birth data from all midwifery hospitals in the city and uses all data for birth registration, allowing it to accurately represent the occurrence of SVN in Beijing without sampling bias. Second, the diagnostic criteria for SVN are relatively objective. These criteria are based on the newborn’s birth weight and gestational age, eliminating potential diagnostic access bias due to inconsistent criteria among different midwifery hospitals.

This study was subject to some limitations. The occurrence of SVN is influenced by economic and cultural conditions. While this study offers a comprehensive representation of SVN occurrence in Beijing, it is important to note the significant variations in economic levels, basic demographic characteristics, and antenatal care quality across different regions of China. Consequently, these findings may not accurately reflect the overall SVN situation in China. In addition, the study did not take into account pregnancy-related diseases. As far as we are aware, pregnancy complications and comorbidities are among the crucial factors that significantly impact pregnancy outcomes. This study investigates the applicability of the new concept for assessing high-risk newborns in Beijing and offers insights for interventions. However, this study did not consider maternal health status; therefore, further research is needed to develop more precise interventions.

No conflicts of interest.

All the participants in this study; and all the public health practitioners involved in Maternal and Children Information System in Beijing for their great efforts in data collection.