Study On The Correlation Between Thyroid Hormone Level In The Early Pregnancy And Gestational Diabetes

【background】Gestational diabetes is seen as a special type of diabetes,It is not only defined as impaired glucose tolerance which is first discovered or occurred during pregnancy,but also defined as a"unclear"dominant diabetes diagnosed during pregnancy.After the opening of the second child policy,the number of the higher age and high risk pregnant women has increased,and the prevalence rate of gestational diabetes in China is increasing.In the past,gestational diabetes mellitus not only affects maternal fetal safety during pregnancy,and even affect the risk of offspring of getting type 2 diabetes mellitus.Health workers all over the world should pay more attention to these diseases and those who suffer a lot from them.Thyroid hormone is an essential hormone for human growth and development.Hyperthyroidism and hypothyroidism can lead to abnormal development,and also bring serious social problems.However,It is important for us to realize that complex physiological changes during pregnancy may also affect the metabolic changes of the thyroid gland.In recent years,there has been a lot of study at domestic and abroad showing that the abnormal levels of thyroid hormones are associated with the incidence of GDM.At present,The number of research with a large sample at domestic between gestational diabetes mellitus and thyroid hormone levels in early pregnancy is small,A lot of the mechanism is not clear.In order to further explore the correlation between the level of thyroid hormone in the early pregnancy and the incidence of GDM,We find a way to predict the occurrence of GDM.It provides a better evidence-based basis for clinical prevention and blocking of the occurrence of GDM.【Objective】Objective to investigate the correlation between thyroid hormone levels in the first trimester of pregnancy and gestational diabetes mellitus（GDM）by analyzing the level of thyroid hormones in the early stage of pregnancy between normal pregnant women and GDM pregnant women.【Methods】According to the inclusion and exclusion criteria,This subject collected a total of 1329outpatient cases strictly in Qingyuan People’s Hospital affiliated to Guangzhou Medical University from January 2013 to 2015 January.All the cases should complete the registration book of general information,complete blood testing,inclouding the thyroid hormones during 11 to 13⁺⁶ weeks in early pregnancy,Besides,in mid pregnancy（24 to28 weeks）they should complete diabetes screening.At last,315 cases of GDM were treated as the observation group;1014 cases of normal glucose tolerance（Normal glucose tolerance,NGT）were treated as the control group.Through statistical analysis of two groups of thyroid hormone levels and general data,we explored the relationship between different hormone types and gestational diabetes mellitus.SPSS 17 statistical software package was used for statistical analysis.The measurement data were expressed by+S,and the Student’s t test was used for the comparison between the groups.The count data is expressed as a percentage,and the classification count data are compared with the chi square test.The correlation analysis with the risk of GDM was analyzed by Logistic regression analysis.The correlation coefficient between variables was analyzed by Pearson.The difference was statistically significant in P<0.05.【Results】1.The comparison between the observation group and the control group about the general information,TC,UA,Blood glucose,FT4,FT3 and TSH;1)The age level between the two groups was（28.7±5.2 Versus 27.5±4.5）years,and the mean value of the two groups was compared,and the difference was statistically significant（P<0.05）.The age of the pregnant women in the observation group was higher than that of the control group.2)the two groups were respectively（1.54±1.02 VS 1.51±0.99）,and the two groups were（22.77±3.61VS 22.34±3.67）kg/m2 respectively.The basic systolic pressure and diastolic pressurebetweenthetwogroupswererespectively（114.32±13.84VS115.42±15.24）and（66.37±8.21VS 65.77±9.32）mmHg,respectively,two groups of TC（4.63±1.16VS 4.57±1.18）mmol/l,two group UA（283.54±119.71VS 271.71±101.68）umol/l,Blood glucose in the beginning of pregnancy（4.85±0.48VS 4.81±0.36）mmol/l,all P>0.05,no statistically significant.3)The level of FT4 between the two groups was（10.04±2.97 Versus 9.59±2.18）pmol/L respectively.The mean value of the two groups was compared,and the difference was statistically significant（P<0.05）,and the FT4 in the observation group was lower than that of the control group.4)The FT3 levels of the two groups were（4.65±0.68 Versus 4.64±1.60）pmol/L respectively,The TSH levels of the two groups were（1.33±1.40 Versus 1.35±1.41）mIU/L,There was no significant difference in mean value between the two groups（P>0.05）.2.The comparison of fasting blood glucose,OGTT 1 h and OGTT 2h between the two groups.1)The level of fasting blood glucose among the two groups was（4.99±0.68 Versus4.51±0.31）mmol/L,The OGTT1h between the two groups was（9.80±1.86 Versus7.62±1.31）mmol/l,The OGTT2h between the two groups was（8.36±1.66 Versus6.43±1.04）mmol/l,respectively.The difference was statistically significant（P<0.05）,The observation group was higher than the control group.3.The distribution and comparison of different subtypes of hypothyroidism between the observation group and the control group.1)The distribution of subtype hypothyroidism among the two groups:the number of in the observation group was 315,of which 3 were combined with clinical hypothyroidism,6 with subclinical hypothyroidism,and 35 with simple hypothyroidemia,of which 269were in the normal range of TSH and FT4.There were only two people in other cases;in the control group,the number of hypothyroidism combined with clinical hypothyroidism was 3,the number of subclinical hypothyroidism in 25 people was 25,and the number of patients combined with hypothyroidemia was 74,of which TSH and FT4 were in the normal range of 889,and other cases were in the other cases.There are 26 people.2)The comparison of the three different subtypes of subtypes of hypothyroidism between the two groups:the comparison of the simple hypothyroidemia among the two groups which P=0.03,the difference was statistically significant,while the two types of hypothyroidism and subclinical hypothyroidism were compared between the two groups.P>0.05,the difference was not statistically significant.4.The comparison of prevalence of different age groups between the observation group and the control group.1)By age grouping,they were divided into elderly（over 35 years）and appropriate age（<35 years）.2)There was a significant difference between the two groups between the elderly and the appropriate age group.X²=11.107 and P=0.001.The proportion of elderly pregnant women in the observation group was higher than that in the control group.5.The correlation between age and FT4 and gestational diabetes mellitus.The outcome of gestational diabetes was defined as GDM 1,non GDM 0,age and FT4 as independent variables,and Logistic regression analysis.The results showed that the low FT4 level was negatively correlated with GDM（OR value=0.912,95%CI:0.851⁰.977）and GDM positive correlation（OR=1.049,95%CI:1.022¹.078）.Regression equation:logit P=-1.1695-0.092（FT4）+0.048（age）,FT4,age interaction verification P>0.05,there is no interaction between them.6.The Pearson analysis of 6.FT4 and other variables:1):FT4 was negatively correlated with age,TC and UA,and R coefficients were-0.121,-0.110 and-0.065,P values were 0.000,0.000 and 0.018,respectively.2):Between FT4 and BMI,basic systolic blood pressure,basal diastolic pressure and blood glucose in Early pregnancy.R coefficient of were-0.035,-0.028,-0.001,0.001 and0.017 respectively,and the P values were all>0.05,and there was no statistical significance.【Conclusion】1.Among the two groups of gestational diabetes and non gestational diabetes,the level of thyroxine（FT4）in the early pregnancy was generally different,the former was generally lower than the latter.2.Between the groups of gestational diabetes and of non gestational diabetes,the age distribution is significantly different.The elder age is more common than the appropriate age in the group of gestational diabetes,who is more likely to be diagnosed as gestational diabetes in the middle of pregnancy.3.FT4 level and age are closely related to GDM in the early pregnancy.Low level FT4 in the early pregnancy and higher age pregnancy are associated with higher incidence of GDM.Therefore,FT4 is a protective factor of GDM,and the risk factor of GDM,and the two factors can provide guiding significance for possible future intervention and prediction.4.During the people with gestational diabetes,the proportion of the simple hypothyroidemia is higher than that of hypothyroidism and subclinical hypothyroidism,The former is more common in this kind of population.