1. GESTATIONALDIABETES MELLITUS

2. DEFINITION & MAGNITUDE A carbohydrate intolerance of varying degrees & severity with onset or first recognition during pregnancy with a probable resolution after the end of pregnancy Not the same as Type 1 or Type 2 Diabetes Varies worldwide & among different racial and ethnic groups within a country Prevalence in India: Chennai : 0.56% (Ramachandran A, 2002) Mysore Parthenon Study: 6% ( Fall C,2000)

3. ETIOLOGY Pregnancy pro-diabetic state Pregnancy  marked insulin resistance  increased insulin requirement  GDM Complicates 4% of all pregnancies 60% to 80 % of women with GDM are obese & experience insulin resistance & GDM

4. Fasting and & postprandial venous plasma sugar during pregnancy

5. Pregnancy Pathophysiology Glucose is a teratogen at high levels Crosses placenta readily while insulin cannot Insulin resistance occurs because hormonal changes associated with pregnancy partially block the effects of insulin Insulin resistance causes glucose to be shunted from mother to the fetus to facilitate fetal growth and development

6. Subsequent increase in insulin resistance causes maternal glucose levels to increase 80% of non-pregnant women Increased insulin resistance Decreased insulin secretion Increased maternal glucose GDM GDM disappears after pregnancy Useful physiologic process out of balance

7. Problems of GDM: fetal Increases the risk of fetal macrosomia Neonatal hypoglycemia Jaundice Polycythaemia Hypocalcaemia, hypomagnesaemia Birth trauma Prematurity Cardiac( including great vessel anomalies)most common Central nervous system7.2% Skeletal: cleft lip/palate, caudal regression syndrome Genitourinary tract: ureteric duplication Gastrointestinal : anorectalatresia

8. Problems of GDM: maternal Weight gain Maternal hypertensive disorders Miscarriages Third trimester fetal deaths Cesarean delivery (due fetal growth disorders) Long term risk of type 2 DM Progression of retinopathy: esp. severe proliferative retinopathy Progression of nephropathy: especially if renal failure + Coronary artery disease: Post MI patients  high risk of maternal death

9. Gestational diabetes diet Water foods are the main concentration. That means plants: vegetables, fruits, grains & legumes Only low-fat and non-fat dairy products Only the leanest cuts of meat with all excess fat trimmed Avoid saturated fats Strongly avoid Trans fats Avoid fast foods, processed foods, microwave foods, high-sugar foods, alcohol & high-sodium foods Drink plenty of fresh water every day Eat 5 or 6 small meals everyday Eat your meals at the same times every day

10. DIAGNOSIS TWO-STEP STRAREGY 50-75g oral glucose challenge Single serum glucose measurement @ 1 hr <7.8 mmol/L(<140mg/dL)  normal >7.8 mmol/L(>140mg/dL) 100-g oral glucose challenge Serum glucose measurements in fasting state, I, II & III hrs Normal values Fasting < 5.8 mmol/L (<105mg/dL) I hr  < 10.5 mmol/L (<190mg/dL ) II hr  < 9.1 mmol/L (<165mg/dL) III hr  < 8.0 mmol/L (<145mg/dL)

11. Overnight fast of at least 8 hours At least 3 days of unrestricted diet and unlimited physical activity > 2 values must be abnormal Urine glucose monitoring is not useful in gestational diabetes mellitus Urine ketone monitoring may be useful in detecting insufficient caloric or carbohydrate intake in women treated with calorie restriction

13. SCREENING Essentially all Indian women have to be screened for gestational diabetes mellitus as they belong to a high risk ethnicity LOW RISK GROUPS: <25 yrs of age BMI <25kg/sq.m No H/O maternal macrosomia No H/O diabetes No H/O D.M in first degree relative Not members of high risk ethnic groups Member of an ethnic group with a low prevalence of GDM No H/O abnormal glucose tolerance No H/O poor obstetric outcome

14. Intermediate risk At least one of the criteria in the list High risk Marked obesity Prior GDM Glycosuria Strong family history Must be done between 24 & 28 weeks of pregnancy Most GDM cases revert to normal after delivery

15. Value of Screening During Current Pregnancy Increased screening, identification and treatment can decrease the morbidity and mortality of GDM Decreased macrosomia, cesarean birth and birth trauma due to a > 4000g infant Decreased neonatal hypoglycemia, hypocalcaemia, hyperbilirubinemia, polycythaemia Identify women at future risk for diabetes and those with insulin resistance

16. Women are generally screened for GDM with glucose challenge test in the late second trimester If result is abnormal  oral glucose tolerance test Abnormal glucose challenge test but no GDM increased risk of future cardiovascular disease They have a lower risk than women who actually did have gestational diabetes In women with glucose intolerance during pregnancy, type 2 diabetes and vascular disease may develop in parallel, which is consistent with the "common soil" hypothesis for these conditions

17. Retesting Negative initial test but risk factors present Obesity >33 years of age Positive 1 hour screen followed by a negative OGGT 3+/4+ glucosuria Low risk  no screening Average risk  at 24-28 weeks High risk  as soon as possible

18. treatment The total first dose of insulin is calculated according to the patient’s weight as follow In the first trimester  weight x 0.7 In the second trimester  weight x 0.8 In the third trimester  weight x 0.9

20. Medical nutrition therapy Approximately 30 kcal/kg of ideal body weight >40-45% should be carbohydrates 6-7 meals daily( 3meals, 3-4 snacks) Bed time snack to prevent ketosis Calories guided by fetal well being/maternal weight gain/blood sugars/ ketones Energy requirements during the first 6 months of lactation require an additional 200 calories above the pregnancy meal plan

21. Fetal monitoring Baseline ultrasound : fetal size At 18-22 weeks  major malformations & fetal echocardiogram 26 weeks onwards  growth and liquor volume III trimester  frequent USG for accelerated growth (abdominal: head circumference)

22. Insulin Management during Labor & Delivery Usual dose of intermediate-acting insulin is given at bedtime Morning dose of insulin is withheld I.V infusion of normal saline is begun Once active labor begins or glucose levels fall below 70 mg/dl, infusion is changed from saline to 5% dextrose & delivered at a rate of 2.5 mg/kg/min Glucose levels are checked hourly using a portable meter allowing for adjustment in infusion rate Regular (short-acting) insulin is administered by iv infusion if glucose levels exceed 140 mg/dl

23. Maternal hyperglycemia in labor: fetal hyperinsulinaemia, worsen fetal acidosis Maintain sugars: 80-120 mg/dl (capillary70-110mg/dl ) Feed patient the routine GDM diet Maintain basal glucose requirements Monitor sugars 1-4 hrly intervals during labour Give insulin only if sugars more than 120 mg/dl Maternal complication Fetal complication Glycemic monitoring: SMBG and targets Fetal monitoring: ultrasound Planning on delivery Long term risks

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