Gestational Diabetes

Gestational Diabetes

Department of Obstetrics and Gynaecology

Classification:
Type I Insulin dependent diabetes mellitus (IDDM)
Type II Non-Insulin dependent diabetes mellitus (NIDDM)
Type III Gestational diabetes mellitus (GDM) or Carbohydrate. Intolerance (ą Insulin) First recognized in pregnancy (True and Pre-existing diabetes)
Type IV Secondary diabetes

Gestational Diabetes
Definition: Glucose intolerance with onset first recognized in pregnancy

Incidence: Variable (1-30%) depending on the level of glucose intolerance used and the ethnicity of the population (United States 2-5%, Denmark 2-3 %). Compared to North European, 11-fold increase in woman from India, 8-fold in Southeast Asia, 6-fold in Arabs, 3-fold in Afro-Caribbean.

Diagnosis:

Risk factors (detects >95% of women with GDA).: Glucosuria: 2+ Boehringer, 1+ Multistix, >5,5 mmol/l

Previous gestational diabetes (33-50% recurrent risk)

Obesity (BMI > 26,9 kg/m2)

Family disposition (first degree relative)

Previous macrosomic baby (>4499 gr) or large for date baby in current pregnancy

In Denmark one of the above risk factors in 36% of the population. Sensitivity 83%. Specificily 65%
Some also suggest unexplained stillbirth, malformation, age >35 years, preterm delivery, and polyhydramnios

Glucose Tolerance Test:
The later in pregnancy the higher the detection rate.
Screening is optimally performed at 24-28 weeks of gestation.
Earlier (in 14-20 weeks) if high degree of suspicion, previous gestational diabetes or 2 of the following 3 criterias:

: Obesity

Previous macrosomia

Family disposition

Blood-glucose = plasma-glucose x 0.86
A fasting plasma glucose level > 7.0 mmol/L (126 mg/dl) or a random plasma > 11.1 mmol/L (200 mg/dl) meets the threshold for the diagnosis of gestational diabetes if confirmed on a subsequent day and precludes the need for any glucose challenge test. When to perform OGTT based on a plasma glucose and glucosuria: 75 mg OGTT if glucosuria (>= 2+ with Boehinger or = 1+ with Bayer), random venous plasma glucose should be recorded.

WHO advise oral 75 mg glucose tolerance test should be carried out if blood glucose is >5.5 mmol/l 2 hours or more after food or > 7 mmol within two hours of food.

CRITERIA: There is no consensus regarding the criteria for the 75 g OGTT in pregnancy.

CRITERIA FOR DIAGNOSIS OF GDM WITH THE 75 G OGTT

Organization	Fasting	1 h PG	2 h PG	Diagnostic Criteria for GDM
WHO	>6,9 mmol/L (126 mg/dL)	Not Measured	>7.7 mmol/L (140 mg/dL)	One abnormal value
Fourth International Workshop/ ADA 1982	>5.2 mmol/L (95 mg/dL)	>9,9mmol/L (180 mg/dL)	>8.5mmol/L (155 mg/dL)	Two or more abnormal values
National Diabetes Data Group (NDDS) 2000	>5.7 mmol/L (95 mg/dL)	>10.5 mmol/L (190 mg/dL)	>9.1 mmol/L (160 mg/dL)	GDM: Two or more abnormal values IGT: One abnormal value

PG: Post glucose ADA: American Diabetes Association NDDS: Diabetes care 2000, suppl 1 S:4

ADA: Random glucose level > 11,1 (200 mg) or fasting >7,0 (126 mg) diagnostic of diabetes Danish guidelines >8,9 mmol in capillary blood or venous plasma.

In Denmark we define a 2-hour level < 9 mmol/L (162 mg/dL) as normal and will repeat the procedure if glucosuria occurs.

Importance of Prognosis: Someone will have preexisting diabetes and therefore first detected during pregnancy.

Decrease incidence of macrosomia (30% of GDA) and shoulder dystocia if diet, insulin and induction are applied.

40-60% developed NIDDM within 15 years and 10-30% would have established eye or renal disease at that time. Modification of lifestyle and diet may prevent or delay NIDDM. Clinical fasting glucose postnatally to look for onset of NIDDM.

MANAGEMENT:
Exercise - in some women the need for insulin may be obligated.
Diet - decrease calorie level
Fiber rich diet
Carbohydrate 55% of total calories
Protein 75-100 gm daily
Fat < 30%, Optimal < 15%
Calories
35 calories per kilo: folic acid a least 1 mg/daily
Obese patients 25 calories per kilo but not < 1800 cal/day

Opthalmoscopy before pregnancy and during each trimester is advised. HbA1C levels (< 8%, 5% risk of malformation, > 10%, 25% risk). 24 hours creatinine clearance and protein.

CTG non stress at 35 weeks earlier, if indicated.

Ultrasound in first trimester, 22 weeks (malformation) inclusive cardiac scan if NIDDM/IDDM.

Blood glucose monitoring Medical Management:
Blood glucose monitoring, aim to have blood glucose between 4 and 7 mmol/L.
Fasting < 6 mmol and 90 minuts after meals < 8 mmol, mean values before and after breakfast and lunch should be less than 7 mmol.
The American College of Obstetricians and Gynecologist recommend the administration of insulin to reduce the risk of macrosomia if one hour postpranded glucose > 130-140 mg/dl /7,2-7,8 mmol/l). HbA1C < 6-7% before 20 weeks and 5-6% after 20 weeks.

Dietitian/Diabetic Nurse, if medical nutritional treatment gives fasting > 5.3 mmol/L (95 mg) or 2-hour > 6.1 mmol/L (120 mg) insulin should be considered.