Critical evaluation of the diagnosis of Gestational Diabetes Mellitus (GDM) Simon Weitzman, MD, MPH

Critical evaluation of the diagnosis of Gestational Diabetes Mellitus (GDM) Diagnostic methods and criteria Screening strategies Maternal and offspring outcomes

Critical evaluation of the diagnosis of Gestational Diabetes Mellitus (GDM) Diagnostic methods and criteria Screening strategies Maternal and offspring outcomes

Diagnostic Methods for GDM n 1-hr. Oral Glucose Challenge Test (GCT) n Oral Glucose Tolerance Test (OGTT) World Health Organization (WHO) National Diabetes Data Group (NDDG) Coustan Modification

Diagnostic criteria for GDM Method Criteria (mg/dl) FPG 1 hr. 2 hr. 3 hr. FPG 1 hr. 2 hr. 3 hr. WHO (75 gr) NDDG (100 gr) Coustan (100 gr) FPG: Fasting plasma glucose

Critical evaluation of the diagnosis of Gestational Diabetes Mellitus (GDM) Diagnostic methods and criteria Screening strategies Maternal and offspring outcomes

Screening strategies for GDM n The approach One-step approach Two-step approach

The 50 gr. GCT (Cutoff >186 mg/dl) n Sensitivity: 38.2% n Specificity: 93.3% n Positive Predictive Value: 78.6 % n Negative Predictive Value : 70.0 %

The 50 gr. GCT (Cutoff >186mg/dl) n Sensitivity: 38.2% n Specificity: 93.3% n Positive Predictive Value:19.5% n Negative Predictive Value: 97.2%

Screening strategies for GDM n The population n Universal screening n High risk groups screening

Universal versus high risk strategy Universal screening 57.4% agreed to screening57.4% agreed to screening 27.7 % GCT positive have abnormal OGTT27.7 % GCT positive have abnormal OGTT Non-participants have more risk factorsNon-participants have more risk factors High Risk Group Screening Would miss > 40% of GDMWould miss > 40% of GDM

Universal screening in the Negev Universal screening in the Negev n 70 % of Jewish and 57% of Bedouins agreed to screening n GCT only in 49% of women n OGTT only in 10% n Overall non- participation: 40%

Critical evaluation of the diagnosis of Gestational Diabetes Mellitus (GDM) Diagnostic methods and criteria Screening strategies Maternal and offspring outcomes

Influence of GDM on the later development of diabetes in the child n Hyperglycemia affects fetal beta-cell function in animals n Intrauterine nutritional deprivation and maternal hyperglycemia increase the risk of diabetes in later life

Maternal and offspring outcomes Characteristic Normal OGTT GDM LGA (%) Gestational age (w) Hospital days

Perinatal characteristics of women with GDM, according to risk factors Characteristic Risk Factors OR( 95%CI) Yes No Characteristic Risk Factors OR( 95%CI) Yes No Cesarean section (%) ( ) Macrosomia (%) ( ) Shoulder Dystocia (%) ( ) Insulin therapy(%) ( )

Plasma glucose levels in non obese, and obese women with previous GDM, after 5-10 years of follow-up

Plasma insulin levels in non obese and obese women with previous GDM, after 5-10 years of follow-up

Logistic regression analysis of factors related to the development of diabetes in women with previous GDM

Glucose tolerance at follow-up in women with previous GDM and healthy controls

Conclusions n J. Nerup said that Type 1 diabetes is the nightmare of geneticists. Paraphrasing his statement, we can say that GDM is the nightmare of epidemiologists. There is controversy about its definition, the best diagnostic method, diagnostic criteria, and the population to be screened.

Conclusions (2) n Despite this confusion, the management of the condition has greatly improved, and the perinatal outcomes of offspring's of GDM mothers are comparable to those of non-diabetic women, except for macrosomia.

Conclusions(3) n There is an increasing body of evidence supporting the risk of developing diabetes mellitus (and particularly type 2 diabetes) among women with previous GDM n Among obese GDM women, even years after delivery, features of insulin resistance can be found