Abstract: Background　Low birth weight infants often have chronic intrauterine hypoxia，their perinatal mortality rate is high，and the long-term physical development is backward and the risk of neurodevelopmental abnormalities is also high. Objective　To analyze the epidemiological characteristics of low birth weight infants and related factors affecting low birth weight infants in Hebei Province. Methods　The maternal and child monitoring information management system of Hebei Province was used to collect data of pregnant women at 37 weeks and above from 22 monitoring sites including 7 provincial and municipal hospitals and 15 county-level hospitals in Hebei Province from 2013 to 2017. Survey indicators included maternal age，birth year，birth season，urban-rural and rural grade distribution of birth hospitals，number of birth checkups，pregnancy times，parity times，fetal gender，the combination with gestational hypertension，gestational diabetes，heart disease and kidney disease，placental abruption，placenta previa，prolonged pregnancy and other related factors. Multivariate Logistic regression was used to analyze the influencing factors of low birth weight infants. Results　Among 250 304 full-term newborns，3 482 cases were low birth weight，with an incidence of 1.39%. There were statistically significant differences in the incidence of low birth weight infants among pregnant women of different ages，birth years，birth seasons，birth regions，urban-rural and rural grade distribution of birth hospitals（P<0.05）. The incidence of low birth weight was the highest（1.65%）among pregnant women with childbearing aged ≥40 years，and the lowest（1.29%）among women aged 30 to 34. The incidence of low birth weight infants was highest in 2015（1.56%）and lowest in 2017（1.29%）. The incidence of low birth weight infants was highest in spring（1.47%）and lowest in autumn（1.29%）. The city of Cangzhou had the highest incidence of low birth weight（1.82%），while Xingtai had the lowest incidence（0.82%）.The incidence of low birth weight infants in provincial and municipal hospitals（1.71%）was higher than that in township hospitals（1.13%）. The incidence of low birth weight infants was highest in tertiary hospitals（1.94%）and lowest in primary hospitals（0.98%）. There were statistically significant differences in age distribution，number of antenatal examinations，the number of pregnancy and parity，fetal sex，proportion of gestational hypertension，proportion of heart disease，proportion of kidney disease，proportion of placental abruption，proportion of placenta previa and proportion of prolonged pregnancy between the low birth weight group and non-low birth weight group（P<0.01）. There was no significant difference in education level and proportion of gestational diabetes mellitus（P>0.05）. Multivariate Logistic regression analysis showed that lower education level of pregnant women，fewer times of birth check-up，female fetus，delivery in provincial and municipal hospitals，gestational hypertension，heart disease，placental abruption，placenta previa were independent risk factors for low birth weight（P<0.05）. Multiple pregnancies，gestational diabetes mellitus and prolonged pregnancy were independent protective factors for low birth weight infants（P<0.05）. Conclusion　The incidence of low birth weight infants varies significantly in time，region and population. Individualized preventive measures should be taken for different regions and populations，such as timely pregnancy and standardized prenatal examination，early detection of potential high-risk factors，timely prevention and treatment to reduce the incidence of low birth weight infants.

Key words: Infant, low birth weight；Epidemiological monitoring；Epidemiologic factors；Root cause analysis；Hebei

摘要： 背景　低出生体重儿多存在慢性宫内缺氧现象，其围生期病死率高，且远期体格发育落后、神经发育异常风险高。目前我国缺乏针对该方向的多中心大样本的调查研究。目的　分析河北省低出生体重儿的流行病学特点及影响低出生体重儿的相关因素。方法　收集河北省妇幼监测信息管理系统2013—2017年在河北省7个省市级医院和15个县级医院，共22个监测点住院分娩的37周及以上孕周的孕产妇资料，调查指标包括孕产妇年龄、出生年份、出生季节、出生医院城乡及等级分布、产检次数、孕次、产次、胎儿性别、孕产妇合并症（妊娠期高血压、妊娠期糖尿病、合并心脏病、合并肾病）、胎盘早剥、前置胎盘、过期妊娠等相关因素。采用多因素Logistic回归分析低出生体重儿的影响因素。结果　250 304例足月新生儿中，低出生体重儿3 482例，发生率为1.39%；不同年龄孕产妇、不同出生年份、不同出生季节、不同出生地区、不同生产医院城乡及等级的低出生体重儿发生率比较，差异均有统计学意义（P<0.05）；其中生育年龄≥40岁孕产妇的低出生体重儿发生率最高（1.65%），30~34岁最低（1.29%）；2015年低出生体重儿发生率最高（1.56%），2017年最低（1.29%）；春季低出生体重儿发生率最高（1.47%），秋季最低（1.29%）；沧州低出生体重儿发生率最高（1.82%），邢台最低（0.82%）；省市级医院低出生体重儿发生率（1.71%）高于乡镇级医院（1.13%）；三级医院低出生体重儿发生率最高（1.94%），一级医院最低（0.98%）。低出生体重儿组孕产妇年龄分布、产检次数、孕次、产次、胎儿性别、妊娠期高血压比例、合并心脏病比例、合并肾病比例、胎盘早剥比例、前置胎盘比例、过期妊娠比例与非低出生体重儿比较，差异有统计学意义（P<0.01），而在文化程度、妊娠期糖尿病比例方面差异无统计学意义（P>0.05）。经多因素Logistic回归分析，结果显示，孕产妇文化程度低、产检次数少、胎儿为女性、省市级医院生产、合并妊娠期高血压、合并心脏病、胎盘早剥、前置胎盘是低出生体重儿的危险因素（P<0.05），多孕次、妊娠期糖尿病、过期妊娠是低出生体重儿的保护因素（P<0.05）。结论　低出生体重儿发病率有明显的时间、地区、人群差异，对不同地区及人群采取个性化预防措施，适时孕育、规范产检，尽早发现潜在的高危因素，及时预防和治疗，减少低出生体重儿发生。

关键词: 婴儿, 出生时低体重；流行病学监测；流行病学因素；影响因素分析；河北