Gestational Diabetes (GDM) Dr.Z Allameh MD

1. Gestational Diabetes(GDM) Dr.Z Allameh MD

2. Prevalence • Diabetes affects 2-4% of pregnancies overall in the U.S. • 90% of cases are Gestational Diabetes • 10% with pre-existing DM (65% type 2) • Higher in African-American, Hispanic, Native-American and Asian women

3. Etiology • During pregnancy, the placenta is secreting diabetogenic hormones, which increase insulin production • growth hormone • corticotropin releasing hormone • human placental lactogen • progesterone

4. Etiology (continued) • GDM occurs when the woman’s pancreas can not function sufficiently to overcome her relative insulin resistance and increased fuel consumption • GDM defined by ACOG as “carbohydrate intolerance first recognized during pregnancy”

5. Low Risk Blood glucose testing not routinely required if all of the following characteristics are present : Member of an ethnic group with a low prevalence of gestational diabetes No known diabetes in first_degree relatives Age less than 25 years Weight normal before pregnancy No history of abnormal glucose metabolism No history of poor obstetrical outcome

6. Average Risk Perform blood glucose testing at 24_28 weeks using one of the following : Average risk_women of Hispanic,African, Native American,South or East Asian origins High Risk_women with marked obesity,strong family history of type 2 diabetes ,prior gestational diabetes,or glucosuria

7. High risk Perform blood glucose testing as soon as feasible : if gestational diabetes is not diagnosed, blood glucose testing should be repeated at 24-28 weeks or at any time a patient has symptoms or signs suggestive of hyperglycemia

8. Risk Factors for GDM • family history • pre-pregnancy weight of 110% of ideal body weight • age >25 years old • previous history of large baby (9 lbs.)

9. Risk Factors (cont’d) • history of abnormal glucose tolerance • ethnic group with higher incidence of Diabetes Mellitus Type 2 • previous unexplained perinatal loss or malformed child • mother was large at birth

10. GDM associated with increased incidence of: • Preeclampsia • Hydramnios • Fetal macrosomia • Birth trauma • Operative deliveries • Later development of DM in mother

11. Increased incidence (cont’d): • Neonatal metabolic complications • Hyperbilirubinemia • Hypocalcemia • Polycythemia • Perinatal mortality • Hypoglycemia

12. Increased incidence (cont’d)due to poor control: • Congenital malformations (4 fold) • caudal regression • spina bifida • anencephalus • heart anomalies • rectal atresia • renal agenesis • situs inversus

13. Screening • Selective • suggested by ADA • USPSTF (“C” recommendation) • Universal • done at 24-28 weeks in all women • may do earlier if suspicious

14. Screening Test • 50 gram oral glucose load • serum glucose 1 hour later • abnormal result is >140 mg/dL • sensitivity improves if patient is fasting • if result is abnormal, the diagnostic test is a 3-hour Glucose Tolerance Test (GTT)

15. Other testing • do diagnostic GTT if: • any random plasma glucose > 200 mg/dL • any fasting plasma glucose > 126 mg/dL • fasting > 86 mg/dL had specificity 76% and sensitivity of 81% for detecting GDM • fasting > 90 mg/dL and HbA1C above normal able to detect macrosomia

16. Diagnostic Test - 3 hour GTT

17. Management • Metabolic control • Diet • Medication • Fetal evaluation • Delivery considerations • Post-partum

18. Metabolic control • “level of glycemia to reduce fetal and neonatal complications in GDM has not been established” • frequent visits • frequent accu-checks • fasting • pre-prandial • post-prandial

19. Metabolic control (cont’d)

20. Diet • caloric intake based on BMI and weight gain • 2,200 to 2,400 kcal • composition • protein 12-20% • carbohydrate 50-60% • fat 20-30%

21. Diet (cont’d)

22. Diet (cont’d) • Timing • breakfast 25% of calories • lunch 30% • supper 30% • 15% as HS snack

23. Medication • Insulin • multiple injections • long and short acting • insulin pump • Oral • not used • recent study using glyburide • NEJM Oct. 19, 2000

24. Fetal Evaluation • Screening for neural tube defects • AFP at 16-20 weeks • Ultrasound at 18-20 weeks • Echo at 20-22 weeks • Third trimester • maternal monitoring of fetal activity • biophysical testing (NST, BPP, CST)

25. Other reasons to increase fetal evaluation • keto-acidosis • pyelonephritis • pre-eclampsia • poor adherence

26. Delivery considerations • Must weigh maternal and fetal risks • With excellent glycemic control and normal fetal surveillance, can await spontaneous labor • If antepartum testing is non-reassuring and lungs are mature - deliver patient

27. Delivery (cont’d) • With high risk patients, goal is to reach pulmonary maturity • vascular disease • poor control • adherence problems • previous still birth

28. Delivery (cont’d) • Risk of complications rises exponentially when birth weight exceeds 4,000 grams • Elective cesarean delivery if birth weight is in excess of 4,500 grams • Neonatal hypoglycemia is related to intrapartum maternal hyperglycemia

29. Delivery (cont’d) • Spontaneous labor • constant infusion of glucose and insulin • frequent accu-checks • Induction/cesarean • give PM insulin and hold AM insulin • start infusion of glucose with labor (after delivery) • accu-checks q 1-2 hours • give insulin for hyperglycemia

30. Post-partum • contraceptive choices • use low dose estrogen/progesterone pills • complications from OCP • one study 5/126 women had cardiovascular complications • another study 0/384 patients, no association • monitor blood pressures while on OCP • will also have to look at lipid profile

31. Post-partum (cont’d) • follow-up testing for Diabetes • 50% chance of developing DM within the next 20 years