Classification Tree Model For Risk Factors Of Gestational Diabetes Mellitus

Objective:(1) To discuss the relationship between the gestational diabetes mellitus(GDM) and premature birth, abnormal amniotic fluid volume, Macrosomia, the fetal respiratory distress and other adverse pregnancy outcomes of pregnancy.(2) To explore the influence factors of the gestational diabetes mellitus, and provide clues to the cause study of the disease, so as to provide the basis for prevention and control.Methods: Questionnaires of pregnant women were collected from the First Affiliated Hospital of Shan xi Medical University between Mar.2012 and Dec.2014. We collected the data of the general demographic characteristics of pregnant women, pregnancy and health status. Patients with the gestational diabetes mellitus as cases, those with no gestational diabetes mellitus as controls. Use a matched case-control study, Epidata 3.1 is used to data record and SPSS16.0, SAS 9.2 to data analysis. By using chi-square test, logistic regression model to discuss the relationship between the gestational diabetes mellitus and premature birth, abnormal amniotic fluid volume, Macrosomia, the fetal respiratory distress and other adverse pregnancy outcomes of pregnancy and to explore the influence factors of the gestational diabetes mellitus. By addition or multiplication interaction analysis discuss the interaction of factors of the gestational diabetes mellitus.Results:(1)Of 6211 newborn singletons, there were 995 pregnant women who were diagnosed with the gestational diabetes mellitus. The incidence of the gestational diabetes mellitus is 16.02%. According to the different pregnancy week, the number of early gestational diabetes is 20 which account for 2.01%, the number of mid-gestational diabetes is 103 which account for 10.35%, the number of late gestational diabetes is 872 which account for 87.64%.(2)Chi-square test showed that differences were statistically significant(P<0.05) in the gestational diabetes mellitus and macrosomia, intrapartum fetal distress. And differences were not statistically significant(P>0.05) in the gestational diabetes mellitus and premature birth, abnormal amniotic fluid, postpartum hemorrhage. Differences were statistically significant(P<0.001) in pregnant age, career, educational level, family income, home, family history of diabetes, hypertensive disorder complicating pregnancy, pre-pregnancy body mass index and GDM. And differences were not statistically significant(P>0.05)in physical activity during pregnancy, career, weight gain during pregnancy and GDM.(3)Unconditional regression model showed that after adjusting some factors, for example, pregnant age, career, educational level, family income, home, parity, gestational weeks, and pre-pregnancy body mass index, the risk of macrosomia in GDM is higher than normal pregnancy(OR=1.677,95%CI:1.282~2.194); the risk of intrapartum fetal distress in GDM is higher than normal pregnancy(OR=1.605,95%CI:1.245~2.069)。(4)Chi-square test showed that differences were not statistically significant(P>0.05) in the early、second、trimester of the gestational diabetes mellitus and macrosomia, intrapartum fetal distress, premature birth, abnormal amniotic fluid, postpartum hemorrhage.(5)Unconditional regression model showed that the risk factor of the gestational diabetes mellitus include: pregnant age older than 35 years old(OR=1.065,95%CI:1.049 ~1.081), secondary or below(OR=1.152,95%CI:1.040~1.276), city(OR=1.821,95%CI: 1.477~2.244),hypertensive disorder in pregnancy(OR=1.367,95%CI:1.095~1.707),family history of diabetes(OR=1.321,95%CI:1.113~1.569), pre-pregnancy overweight and obesity(OR=1.975,95%CI:1.726~2.260),excess weight gain during pregnancy(OR=1.150,95%CI: 1.039~1.274)。(6)Three explanatory variables were selected from the model, namely pre-pregnancy body mass index, pregnant age, family income. The primary risk factor of the gestational diabetes mellitus is pre-pregnancy body mass index. The proportion of pre-pregnancy overweight and obesity in GDM(27.2%) is higher than those who were normal weight(14.1%) and low weight(9.9%),pre-pregnancy overweight and obesity became the main risk factor of the gestational diabetes mellitus.In pregnant women who were overweight and obesity before pregnancy, family income became the main factor which affect the incidence of GDM, the risk of the incidence of GDM in pregnant women whose family income were no more than 2000 per person per month is lower than those who were not. In the latter pregnant age became the main factor which affect the incidence of GDM, the risk of the incidence of GDM in pregnant women whose pregnant age were equal or greater than 35 is higher than those who were not. In pregnant women who were normal weight before pregnancy, pregnant age became the main factor which affect the incidence of GDM, the risk of the incidence of GDM in pregnant women whose pregnant age were equal or greater than 35 is higher than those who were not. In the latter educational level became the main factor, the risk of the incidence of GDM in pregnant women who were below technical secondary school is higher than hose who were not.(7)Use classification tree model to filter the possible factors between which existed interactions. The result showed that there existed addictive interaction between pre-pregnancy body mass index and pregnant age(RERI=2.387,AP=0.705, S=-687.726), family income and pregnant age(RERI=6.804,AP= 0.895,S=-32.124),multiplication interaction was not found between them.Conclusions:(1)The risk of the incidence of macrosomia, intrapartum fetal distress in pregnant women who were diagnosed with GDM is higher significantly than those who were not.(2)The risk factors of GDM include pregnant age older than 35 years old, secondary or below, city, hypertensive disorder in pregnancy, family history of diabetes, pre-pregnancy overweight and obesity and excess weight gain during pregnancy.(3)The primary risk factor of the gestational diabetes mellitus is pre-pregnancy body mass index. According to the study pre-pregnancy body mass index should keep less than 24kg/m2.We are supposed to be aware of these factors to make the GDM rate lower and decrease the incidence of macrosomia, intrapartum fetal distress to promote health of mother and baby for further.(4)Those pregnant women who were pre-pregnancy overweight and obesity, 2000 yuan or more per month per person, equal or more than 35 years old should be paid most attention in order to prevent GDM from happening.(5)The result showed that there existed addictive interaction between pre-pregnancy body mass index and pregnant age, family income and pregnant age, multip-lication interaction was not found between them.