陕西省孕龄妇女既往生育史与小于胎龄儿的多水平Logistic回归分析

Multilevel Logistic regression model analysis between pregnancy history of women and small-for-gestational age of infants in Shaanxi Province

目的分析既往生育史与小于胎龄儿发生的关系,为小于胎龄儿的预防提供理论依据。方法采用分层多阶段随机抽样方法获得的“陕西省出生缺陷现状及其危险因素调查”数据,排除出生体重、孕周和母亲基本情况缺失的记录后,共纳入27 253名妇女进入本次研究。使用SAS 8.0的Proc nlmixed过程,以新生儿是否为小于胎龄儿为因变量,以孕次、产次、自然流产史、人工流产史、药物流产史、引产史、异位妊娠史、葡萄胎史和剖宫产史为自变量,建立以个体为水平1、区县为水平2的两水平Logistic回归模型。Model 1仅研究小于胎龄儿和既往生育史之间的关系,Model 2在Model 1的基础上校正了胎儿性别、母亲年龄、母亲学历、母亲职业、母亲民族、孕期有无服用叶酸、孕期有无贫血、产检次数共8个危险因素。结果陕西省小于胎龄儿的发生率为12.1%,高于全国平均水平。Model 1中产次≥3次相较于产次≤2次是小于胎龄儿发生的危险因素(OR:1.54,95%CI:1.20~1.98),有人工流产史可以降低小于胎龄儿的发生(OR:0.76,95%CI:0.63~0.92)。Model 2在校正了相应的混杂因素后,仅产次≥3次是小于胎龄儿发生的危险因素(OR:1.57,95%CI:1.23~2.03)。结论在临床中应当重点关注高产次的孕妇,同时加强对孕产妇的健康教育,减少小于胎龄儿的发生。

Objective To explore the relationship between women s pregnant history of and infants small-for-gestational-age (SGA) so as to provide a theoretical basis for the prevention of SGA.Methods After excluding the missing records about the basic situation, gestational age and birth weight, we recruited 27,253 women in our study by using the data from the Investigation on the Status of Birth Defects and Their Risk Factors in Shaanxi Province , which were obtained by using multistage stratified random sampling method.The proc nlmixed process of SAS 8.0 was used to establish a two-level logistic regression model, which level 1 was for the individual and level 2 for the county.In our model, the dependent variable was SGA, and the independent variables were gravidity, parity, natural abortion, artificial abortion, drug abortion, induced abortion, ectopic pregnancy, hydatid pregnancy, and cesarean section.We established two models in this study:Model 1 only included the variable of the past pregnancy history of women, Model 2 was adjusted for variables in Model 1 plus fetus gender, mother s age, mother s education, mother s occupation, mother s nationality, whether the women ingested folic acid or had anemia during pregnancy, and whether prenatal checkup ≥5 times.Results The incidence of SGA was 12.1% in Shaanxi Province, higher than the nation level.In Model 1, compared with parity ≤2 times, parity ≥3 times was a risk factor for SGA ( OR :1.54, 95% CI :1.20-1.98), and women who had induced abortion had decreased incidence of SGA ( OR :0.76, 95% CI :0.63-0.92).After adjustment of the corresponding factors, only parity ≥3 times was a risk factor for SGA ( OR :1.57, 95% CI :1.23-2.03) in Model 2.Conclusion In order to reduce the occurrence of SGA, we should pay more attention to pregnant women who have the history of high parity, and strengthen the health education for them.