Diagnosis of GDM Dr m .mortazavi

Diabetes in Pregnancy: 2 Categories Pregestational diabetes Gestational diabetes Pregnancy in pre-existing diabetes Type 1 diabetes Type 2 diabetes Diabetes diagnosed in pregnancy

Definition Historically, the term “gestational diabetes” has been defined as onset or first recognition of abnormal glucose tolerance during pregnancy. The American College of Obstetricians and Gynecologists (ACOG) continues to use this terminology Dr. sh. Alamdari 11/16/2018

Definition In recent years, the International Association of Diabetes and Pregnancy Study Group (IADPSG), the American Diabetes Association (ADA), the World Health Organization (WHO), and others have attempted: to distinguish women with probable preexisting diabetes that is first recognized during pregnancy from those whose disease is a transient manifestation of pregnancy-related insulin resistance Dr. sh. Alamdari 11/16/2018

Definition This change acknowledges the increasing prevalence of undiagnosed type 2 diabetes in nonpregnant women of childbearing age. These organizations typically use the term “gestational diabetes” to describe diabetes diagnosed during the second half of pregnancy, and terms such as “overt diabetes” or “diabetes mellitus in pregnancy” to describe diabetes diagnosed early in pregnancy, when the effects of insulin resistance are less prominent. Dr. sh. Alamdari 11/16/2018

Risk factors Obstet Gynecol Clin N Am 37 (2010) 255–267 11/16/2018 Dr. sh. Alamdari 11/16/2018

Women at low risk of gestational diabetes are younger (<25 years of age), non-Hispanic white, with normal BMI (<25 kg/m2), no history of previous glucose intolerance or adverse pregnancy outcomes associated with gestational diabetes, and no first degree relative with diabetes. Only 10 percent of the general obstetric population in the United States meets all of these criteria for low risk of developing gestational diabetes, which is the basis for universal rather than selective screening Dr. sh. Alamdari 11/16/2018

Prevalence of GDM Epidemiology of glucose intolerance and GDM in women of child bearing age, Diabetes Care, 21, 1998

Fetal effects Spontaneous abortion (poor glycemic control: Hb A1c > 7 (12) % or pre parendial glucose concentrations >120 mg/dL) Preterm delivery (26% vs. 6.8% - 60% were indicated preterm births due to obstetrical or medical complications) Malformations (5% - isolated cardiac defect, caudal regression sequence) Due to: alterations in cellular lipid metabolism, excess production of toxic superoxide radicals, activation pf programmed cell death)

Fetal effects Altered fetal growth Due to: congenital malformations, advanced maternal vascular disease, maternal hyperglycemia: blood glucose chronically > 130 mg/dL) Unexplained fetal demise Usually after 35 weeks , typically LGA Uncontrolled hyperglycemia …… elevated lactic acid levels …. Fetal acidosis

Fetal effects Explicable still births Placental insufficiency, vascular complications, maternal ketoacidosis Hydramnios Due to fetal polyuria (poor maternal glucose control)

Neonatal effects Respiratory distress syndrome (delayed lung maturation, preterm birth) Hypoglycemia (due to hyperplasia of the fetal β- islet cells induced by chronic maternal hyperglycemia) Hypercalcemia Strict (18%) vs. customary control group (1/3) Aberrations in mg-ca economy, asphyxia, preterm birth

Neonatal effects Hyperbilirubinemia and polycythemia Polycythemia Fetal response to relative hypoxia due to: Hyperglycemia- mediated increase in maternal affinity for oxygen + insulin like growth factors

Neonatal effects hypertrophic Cardiomyopathy Long-term cognitive development Inheritance of diabetes

Maternal effects Preeclampsia vascular complication preexisting proteinuria Preterm labor Diabetic nephropathy ( pregnancy does not worsen diabetic nephropathy) Diabetic neuropathy Diabetic ketoacidosis Infections Almost all types of infections are increased Candida vulvovaginitis, urinary & respiratory tract infections, puerperal pelvic sepsis

Fetal macrosomia Excessive shoulder & trunk fat Shoulder dystocia or cesarean delivery

gestational diabetes Underlying pathophysiology of GDM is similar with T2DM. Clinical recognition of GDM is important because therapy can reduce pregnancy complications and potentially reduce long term sequel in the offspring.

Need a Preconception Checklist for Women with Pre-existing Diabetes 2013 1. Attain a preconception A1C of ≤7.0% (if safe) 2. Assess for and manage any complications 3. Switch to insulin if on oral agents 4. Folic Acid 5 mg/d: 3 months pre-conception to 12 weeks post-conception 5. Discontinue potential embryopathic meds: Ace-inhibitors/ARB (prior to or upon detection of pregnancy) Statin therapy Script:

Screen for Complications: Pre-pregnancy and Intrapartum Screening for: Retinopathy: Need ophthalmological evaluation Nephropathy: Assess creatinine + urine microalbumin / creatinine ratio (ACR) Women with microalbuminuria or overt nephropathy are at ↑ risk for hypertension and preeclampsia

Recommendation 3: Preconception Care (continued) Supplement their diet with multivitamins containing 5 mg of folic acid at least 3 months pre-conception and continuing until at least 12 weeks post-conception [Grade D, Level 4]. Supplementation should continue with a multivitamin containing 0.4-1.0 mg of folic acid from 12 weeks postconception through to 6 weeks postpartum or as long as breastfeeding continues [Grade D, Consensus].

Recommendation 4: Preconception Care Women with type 2 diabetes who are planning a pregnancy should switch from non-insulin antihyperglycemic agents to insulin for glycemic control [Grade D, Consensus]. Women with pregestational diabetes who also have PCOS may continue metformin for ovulation induction [Grade D, Consensus].

Are there clear threshold glucose levels above which the risk of adverse neonatal or maternal outcomes increases? NO

Selective vs. Universal? SCREENING Selective vs. Universal? One step vs. two step?

Thus, universal screening is recommended. Whom to be screened ? low risks of GDM should have all below criteria: <25 yrs non-Hispanic white BMI <25 kg/m2 no history of previous glucose intolerance or adverse pregnancy outcomes associated with GDM no first degree relative with diabetes Only 10% of the general obstetric population meets all of these criteria. 2.7-20% of women diagnosed with GDM have no risk factors. Thus, universal screening is recommended. Obstet Gynecol 2013; 122:406.

Controversies in Diagnosis of GDM GDM & Controversy are old friends. Lack of consensus for the diagnosis of GDM has been a problem ever since the existence of GDM was recognized. ► Who should be screened? ► When should be screened? ► How should be screened? ►What should be the diagnostic criteria? A critical question is whether treatment of GDM improves outcomes.

Evolution of Diagnostic Criteria 1979 : NDDG modified these number for venous plasma (The original O,Sullivan & Mahan criteria were increased by 14%) Test sample timing Plasma Glucose value Fasting (mg%) 105 (90) 1 hour (mg%) 190 (165) 2 hour (mg%) 165 (145) 3 hour (mg%) 145 (135) Two or more Abnormal Value

Evolution of Diagnostic Criteria 1982 : Carpenter & Coustan provided their own modification of the numbers ADA & ACOG endorsed Carpenter and Coustan criteria Carpenter Coustan Somogyi-Nelson Vs. Glucose oxidase Whole blood Vs. Plasma - 5 mg/dl + 14%

Two or more Abnormal Value Carpenter & Coustan OGTT,100g , 3- hour Test Test sample timing Plasma Glucose value Fasting (mg%) 95 1 hour (mg%) 180 2 hour (mg%) 155 3 hour (mg%) 140 Two or more Abnormal Value

Clinical Recommendations Since the 1970s, the standard test for diagnosis of GDM in the USA ACOG : Two step approach - GCT : 50-g glucose, at 24-28 weeks, any time of day • Plasma glucose 1-hour later : ● <140 mg/dl = normal ● 140 – 199 mg/dl = OGTT ● ≥200 mg/dl = GDM -100-g, 3-hour diagnostic OGTT: 1 2

Glucose Challenge Test : GCT GCT : 50-g glucose, at 24-28 weeks, any time of day • Plasma glucose 1-hour later : ● >140 mg/dl = 80% Detection ● >130 mg/dl = 90% Detection > 130 mg/dl : Increases OGTT 2 times more

Screening for DM in high risk women before 24 weeks of gestation Random glucose ≥200mg/dl Or Fasting Glucose ≥92mg/dl Fasting Glucose (2nd measurement) < 92mg/dl Normal 92-125 mg/dl GDM ≥126mg/dl Diabetes Mellitus

NIH Recommendations ( 2013) Two step approach - GCT : 50-g glucose, at 24-28 weeks, any time of day • Plasma glucose 1-hour later : ● <140 mg/dl = normal ● 140 – 199 mg/dl = OGTT ● ≥200 mg/dl = GDM : 1

- 75-g glucose, 2-hour OGTT , at 24-28 weeks, NIH Recommendations ( 2013) 2 - 75-g glucose, 2-hour OGTT , at 24-28 weeks, Test sample timing Plasma Glucose value Fasting (mg%) 95 1 hour (mg%) 195 2 hour (mg%) 162 One abnormal Value is enough

One step approach 75-g glucose, 2-hour OGTT, at 24-28 weeks, IADPSG recommendation(2010) Supported by ADA One step approach 75-g glucose, 2-hour OGTT, at 24-28 weeks, Test sample timing Plasma Glucose value Fasting (mg%) 92 1 hour (mg%) 180 2 hour (mg%) 153 One abnormal Value is enough Subsequently, some commentaries and debate challenged this recommendation

- 75-g glucose, 2-hour OGTT , at 24-28 weeks, NIH Recommendations ( 2013) 2 - 75-g glucose, 2-hour OGTT , at 24-28 weeks, Test sample timing Plasma Glucose value Fasting (mg%) 95 1 hour (mg%) 195 2 hour (mg%) 162 One abnormal Value is enough

Self monitoring of blood GLC We recommend self-monitoring of blood glucose in all pregnant women with GDMor overt DM(1++++) suggest testing before and either 1 or 2 hours after the start of each meal and, as indicated, at bedtime and during the night(2++oo)

Glycemic targets We recommend pregnant women with overt or GDM strive to achieve a target preprandial blood glucose <95 mg/dL( 1++oo) for fasting ,1+ooo) for other meals. We suggest that an even lower fasting blood glucose target of <90 mg/dL be strived for(2 +ooo) if this can be safely achieved without undue hypoglycemia. We suggest pregnant women with overt or GDM strive to achieve target blood glucose levels 1 hour after the start of a meal <140 mg/dL and 2 hours after the start of a meal <120 mg/dL (2+ooo) We suggest pregnant women with overt DM ,HbA1C <7% (ideally <6.5%). (2+ooo)

Glycemic Targets Preconceptionally for Women with Overt Diabetes and During Pregnancy for Women With Either Overt Diabetes or Gestational Diabetesa

Nutrition therapy We recommend MNT for all pregnant women with overt or GDM to help achieve and maintain desired glycemic control while providing essential nutrient requirements. (1++oo)

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