Value of fasting plasma glucose to screen gestational diabetes mellitus before the 24th gestational week in women with different pre-pregnancy body mass index

Background:Gestational diabetes mellitus(GDM)is usually diagnosed between 24th and 28th gestational week using the 75-g oral glucose tolerance test(OGTT).It is difficult to predict GDM before 24th gestational week because fast plasma glucose(FPG)decreases as the gestational age increases.It is controversial that if FPG≥5.1 mmol/L before 24th gestational week should be intervened or not.The aim of this study was to evaluate the value of FPG to screen GDM before 24th gestational week in women with different pre-pregnancy body mass index(BMI).Methods:This was a multi-region retrospective cohort study in China.Women who had a singleton live birth between June 20,2013 and November 30,2014,resided in Beijing,Guangzhou and Chengdu,and received prenatal care in 21 selected hospitals,were included in this study.Pre-pregnancy BMI,FPG before the 24th gestational week,and one-step GDM screening with 75 g-OGTT at the 24th to 28th gestational weeks were extracted from medical charts and analyzed.The pregnant women were classified into four groups based on pre-pregnancy BMI:Group A(underweight,BMI<18.5 kg/m^2),Group B(normal,BMI 18.5-23.9 kg/m^2),Group C(overweight,BMI 24.0-27.9 kg/m^2)and Group D(obesity,BMI≥28.0 kg/m^2).The trend of FPG before 24th week of gestation was described,and the sensitivity and specificity of using FPG before the 24th gestational week to diagnose GDM among different pre-pregnancy BMI groups were reported.Differences in the means between groups were evaluated using independent sample t-test and analysis of variance.Pearson Chi-square test was used for categorical variables.Results:The prevalence of GDM was 20.0%(6806/34,087)in the study population.FPG decreased gradually as the gestational age increased in all pre-pregnancy BMI groups until the 19th gestational week.FPG was higher in women with higher pre-pregnancy BMI.FPG before the 24th gestational week and pre-pregnancy BMI could be used to predict GDM.The incidence of GDM in women with FPG≥5.10 mmol/L in the 19th to 24th gestational weeks and pre-pregnancy overweight or obesity was significantly higher than that in women with FPG≥5.10 mmol/L and pre-pregnancy BMI<24.0 kg/m^2(78.5%[62/79]vs.52.9%[64/121],χ^2=13.425,P<0.001).Conclusions:FPG decreased gradually as the gestational age increased in all pre-pregnancy BMI groups until the 19th gestational week.Pre-pregnancy overweight or obesity was associated with an increased FPG value before the 24th gestational week.FPG≥5.10 mmol/L between 19 and 24 gestational weeks should be treated as GDM in women with pre-pregnancy overweight and obesity.

Maternal Thyroid-Stimulating Hormone Level and Thyroid Peroxidase Antibody Status in the First and Second Trimester of Pregnancy and Their Relationship with the Risk of Gestational Diabetes Mellitus

Objective:To investigate thyroid-stimulating hormone(TSH)levels and thyroid peroxidase antibody(TPOAb)in early pregnancy and to estimate the risk of development of gestational diabetes mellitus(GDM).Methods:The levels of TSH,free thyroxine,free triiodothyronine,and TPOAb were retrospectively evaluated in 2333 pregnant women.All women recruited were divided into groups of TSH high(H),TSH low(L),TSH(H)TPOAb positive(+),TSH(H)TPOAb negative(-),TSH normal(N)TPOAb(+),TSH(L)TPOAb(+),TSH(L)TPOAb(-),and estimated the risk of GDM.Results:TSH level(X^(2)=13.0024,P=0.0015)and TSH combined TPOAb(X^(2)=20.0038,P=0.0012)were correlated to development of GDM.The level of TSH in 95 women was increased,and in 216 women were decreased.Of the 2333 pregnant women,546 patients were diagnosed with GDM,with a prevalence of 23.40%.The prevalence of GDM was 35.78%and 28.70%for the TSH high(H)and TSH low(L)pregnant women,respectively.The increased TSH(P=0.0013,odds ratio:2.09,confidence interval:1.34-3.28)was correlated to increase GDM incidence.TSH(H)TPOAb(+)(n=29),TSH(H)TPOAb(-)(n=58),TSH normal(N)TPOAb(+)(n=265),TSH(L)TPOAb(+)(n=30),TSH(L)TPOAb(-)(n=154)were in this study.The prevalence of GDM was 51.72%,29.31%,23.02%,26.67%,and 29.87%for the TSH(H)TPOAb(+),TSH(H)TPOAb(-),TSH(N)TPOAb(+),TSH(L)TPOAb(+),and TSH(L)TPOAb(-)pregnant women,respectively.Only the TSH(H)TPOAb(+)pregnant women had a significant higher incidence of GDM(P=0.0018,odds ratio:3.63,confidence interval:1.62-8.16).Trimester specific results showed that only second trimester had higher GDM risk either analyze TSH or the combination of TSH and TPOAb.Conclusion:Elevated TSH level and TPOAb positive in the second trimester of pregnancy were correlated to an increased risk of GDM.