Gestational Diabetes(GDM)

Dr.Z Allameh MD

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

Etiology

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

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”

• 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

• 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

• 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

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.)

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

GDM associated with increased incidence of:

• Preeclampsia• Hydramnios• Fetal macrosomia• Birth trauma• Operative deliveries• Later development of DM in

mother

Increased incidence (cont’d):

• Neonatal metabolic complications – Hyperbilirubinemia– Hypocalcemia– Polycythemia– Perinatal mortality– Hypoglycemia

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

Screening

• Selective– suggested by ADA – USPSTF (“C” recommendation)

• Universal– done at 24-28 weeks in all women– may do earlier if suspicious

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)

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

Diagnostic Test - 3 hour GTT

4th International Workshop –Conference on GDM

Expert Committee on Diagnosis andClassification of DM

Time Measurementmg/dL

Time Measurementmg/dL

Fasting >95 Fasting >105

1 hour >180 1 hour >190

2 hour >155 2 hour >165

3 hour >140 3 hour >145

Management

• Metabolic control– Diet– Medication

• Fetal evaluation• Delivery considerations• Post-partum

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

Metabolic control (cont’d)

TIME GOAL (mg/dL)

Fasting 60-90

Pre-prandial 60-105

1 hour post <130-140

2 hour post <120

2 am – 6 am 60-90

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%

Diet (cont’d)

Current Weight in relation toIdeal Body Weight

Daily Caloric Intake (kcal/kg)

<80% 35-40

80-120% 30

120-150% 24

>150% 12-15

Diet (cont’d)

• Timing – breakfast 25% of calories – lunch 30%– supper 30%– 15% as HS snack

Medication

• Insulin– multiple injections– long and short acting– insulin pump

• Oral– not used– recent study using glyburide

• NEJM Oct. 19, 2000

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)

Other reasons to increase fetal evaluation

• keto-acidosis• pyelonephritis• pre-eclampsia• poor adherence

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

Delivery (cont’d)

• With high risk patients, goal is to reach pulmonary maturity– vascular disease– poor control– adherence problems– previous still birth

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

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

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

Post-partum (cont’d)

• follow-up testing for Diabetes• 50% chance of developing DM

within the next 20 years