The Effect Of Gestational Diabetes Mellitus With Subclinical Hypothyroidism On Adverse Pregnancy Outcome

Objective:To further explore whether Gestational Diabetes Mellitus（GDM）has a high risk of being combined with subclinical hypothyroidism（SCH）and adverse pregnancy outcome,and whether the risk will be increased with the increasing of abnormal blood glucose level;to explore whether GDM with SCH will further aggravate adverse pregnancy outcome;to explore whether levothyroxine（L-T₄）can improve the adverse pregnancy outcome of GDM with SCH.Methods:The pregnant women of singleton pregnancies hospitalized in the Department of Obstetrics of Hunan Provincial People’s Hospital from January 2012 to July 2018 were collected.The pregnant women with previous medical history were excluded.The general conditions,the results of clinical biochemical indicators and oral glucose tolerance test（OGTT）and thyroid function in late pregnancy were collected.439pregnant women who met the enrollment criteria were divided into non-GDM group and GDM group according to OGTT results.The GDM group was divided into the GDM1 group（GDM uncombined SCH group）and GDM2 group（GDM combined with SCH group）according to thyroid function during late pregnancy,and a group（one abnormal blood glucose level）,b group（two abnormal blood glucose levels）and c group（three abnormal blood glucose level）according to the abnormal number of blood glucose levels.The GDM2 group was divided into the interventional group（treated with L-T₄）and the non-interventional group（not treated with L-T₄）according to whether received L-T₄ treatment or not.The differences in the indicators and the pregnant outcome between the groups of pregnant women were assessed.The case group meet the GDM diagnostic criteria established by the Chinese Diabetes Society in2018,the subclinical hypothyroidism diagnostic criteria established by Chinese Society of Endocrinology（CSE）in 2018;the blood glucose level of the non-GDM group did not meet the diagnosis of diabetes.Results:1.Compared with non-GDM group,GDM group had smaller gestational age,larger body weight and body mass index（BMI）,higher thyroid stimulating hormone（TSH）,fasting blood glucose（FBG）,one hour postprandial blood glucose（1hPBG）,two hour postprandial blood glucose（2hPBG）,randomized blood glucose at admission and the rate of SCH,premature rupture of membranes,preterm birth.The difference was statistically significant（P<0.05）.（Table 1-Table 3）2.Compared with the GDM1 group,the GDM2 group had smaller gestational age,higher FBG,1hPBG,2hPBG,randomized blood glucose at admission,TSH during late pregnancy,and the rate of preterm birth.The difference was statistically significant（P<0.05）.（Table 4-Table 6）3.Compared with the group a,the group b had higher TSH during late pregnancy,the rates of preterm birth and SCH,and the weight,BMI,TSH during late pregnancy,and the rates of preterm and SCH in group c were higher.The difference was statistically significant（P<0.05）.Compared with group b,the body weight,BMI,TSH during late pregn-ancy and the rate of preterm birth were higher in the group c.The difference was statistically significant（P<0.05）.（Table 7-Table 9）4.Compared with the non-interventional group,the body weight,BMI is smaller,the FBG,randomized blood glucose at admission,TSH during late pregnancy were lower,an the rate of premature delivery and premature rupture of membranes was lower in the interventional group.The difference was statistically significant（P<0.05）.（Table 10-Table 12）Conclusion:1.The pregnant women with GDM have a high risk of suffering from SCH and adverse pregnancy outcome than pregnant women without GDM,and the risk will be increased with the increasing of abnormal level of blood glucose.2.GDM with SCH can further increase the adverse pregnancy outcome.3.L-T₄ can improve the adverse pregnancy outcome of pregnant women with GDM combined with SCH.