Low risk: blood glucose testing is not required if all the following are present:
<25-years of age
BMI <25 kg/m2
No maternal h/o macrosomia or GDM
No h/o DM in 1° relatives
Not member of high-risk ethnic groups: Native Americans, Hispanics, African-American.
Average risk women: Perform blood glucose testing at 24 - 28 wk of gestation using one of the following:
Two-procedure: 50 g oral glucose challenge test (OGCT), if BG is 140 mg/dL (7.8 mmol/L) or greater after an hour, do a diagnostic 3 Hr,OGTT. For OGTT, patient will have to fast 8-10 hrs ON and receive 100-g glucose load after a FPG is obtained:
Fasting: 95 mg/dL
1h: >180 mg/dL
2h: >155 mg/dL
3h: >140 mg/dL
(2 or more of the values must be met for Dx of GDM). Conservative criteria.
If only 1 postglucose load measurement is abnormal, the diagnosis is impaired glucose tolerance.
High-risk women: Perform blood glucose testing as soon as feasible, using the procedures described above:
If GDM is not Dx, blood glucose testing should be repeated at 24-28 wk of gestation or at any time a Pt has sx suggestive of hyperglycemia.
Assess risk for GDM at the first pernatal visit.
Pregnant women with GDM are at higher risk of developing preeclampsia, delivering infants who are large for their gestational age, birth lacerations. There is a 40% chance of women with GDM (within 10 years after index pregnancy) to develop DM. All such women should have careful monitoring and prevention.
Fetuses are at increased risk of hypoglycemia, and birth trauma (brachial plexus injury)..
Tx: 2-step intervention.
Diet
Insulin, if diet alone does not work to control BS (fasting glucose <100 mg/dL) and 2-h post-prandial <126 mg/dL. Use of oral hypoglycemic agent glyburide has become popular (unproven), but insulin remains treatment of choice.