GESTATIONALDIABETES MELLITUS

DEFINITION & MAGNITUDEA carbohydrate intolerance of varying degrees & severity with onset or first recognition during pregnancy with a probable resolution after the end of pregnancyNot 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)

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

FASTING AND & POSTPRANDIAL VENOUS PLASMA SUGAR DURING

PREGNANCY

Fasting2h

postprandial

Result

<100 mg/dl < 145mg/ dl Not diabetic

>125 mg/ dl >200 mg/ dl Diabetic

100-125 mg/dl 125-200 mg/dlBorder line indicates

glucose tolerance test

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

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

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 system7.2% Skeletal: cleft lip/palate, caudal regression syndrome Genitourinary tract: ureteric duplication Gastrointestinal : anorectal atresia

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

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 allexcess 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

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)

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

SCREENING Essentially all Indian women have to be

screenedfor gestational diabetes mellitus as they belongto 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

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

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

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

RETESTINGNegative initial test but risk factors

presentObesity>33 years of agePositive 1 hour screen followed by

a negative OGGT3+/4+ glucosuria

Low risk no screeningAverage risk at 24-28 weeksHigh risk as soon as possible

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

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

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)

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

Maternal hyperglycemia in labor: fetal hyperinsulinaemia, worsen fetal acidosis

Maintain sugars: 80-120 mg/dl (capillary70-110mg/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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