Best Dx/Best Rx: Gestational Diabetes = Mellitus

From: Subject: Best Dx/Best Rx: Gestational Diabetes Mellitus Date: Wed, 3 Jun 2009 21:59:13 -0700 MIME-Version: 1.0 Content-Type: multipart/related; type="text/html"; boundary="----=_NextPart_000_02A4_01C9E496.8838F030" X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_02A4_01C9E496.8838F030 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Content-Location: http://www.acpmedicine.com/acp/newrxdx/rxdx/dxrx0904.htm Best Dx/Best Rx: Gestational Diabetes = Mellitus

Gestational Diabetes Mellitus=20

Amy Aronovitz, M.D., and Boyd E. = Metzger,=20 M.D.
Northwestern University Feinberg School of Medicine =

De= finition/Key=20 Clinical Features
Diffe= rential=20 Diagnosis
Best = Tests
Best = Therapy
Best = References

Definition/Key Clinical Features

Glucose intolerance first = identified=20 during pregnancy=20
Affects 5%=967% of pregnant = women, and=20 incidence is increasing=20
Likely reverts to normal = after=20 delivery=20
Associated with high risk of = future=20 glucose intolerance during pregnancy and diabetes outside of pregnancy = (~ 50%=20 within 5 yr)=20
Risks to fetus include = perinatal=20 mortality, macrosomia, obesity, abnormal glucose metabolism, = hypoglycemia,=20 hypocalcemia, jaundice

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Differential Diagnosis

Type 1 diabetes=20
Type 2 diabetes

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Best Tests

Assess patient's risk of gestational diabetes mellitus (GDM)=20
- Low risk: blood glucose testing not routinely required=20
  - Patient exhibits all of the following characteristics:=20
    - Member of an ethnic group with low GDM prevalence=20
    - No known diabetes in first-degree relatives=20
    - Age < 25 yr=20
    - Normal weight before pregnancy=20
    - Normal weight at birth=20
    - No history of abnormal glucose metabolism
  - Fewer than 10% of women in the United States fit into this = category=20
- Average risk: test blood glucose at 24=9628 wk gestation=20
  - All patients not classified as low or high risk are considered = to be=20 at average risk
- High risk: test blood glucose as soon as possible and repeat at = 24=9628=20 weeks if initial tests negative=20
  - Patient has marked obesity; strong family history of type 2 = diabetes=20 mellitus; or history of GDM, impaired glucose metabolism, or = glucosuria=20
Two-step testing=20
- Glucose challenge test (GCT): measure plasma glucose level 1 hr = after=20 ingestion of 50 g glucose=20
- If plasma glucose > 140 mg/dl on GCT, perform 3-hr 100 g oral = glucose=20 tolerance test (OGTT); see criteria below
One-step testing: OGTT only; diagnosis of GDM requires that plasma = glucose=20 levels meet two of the following criteria:=20
- Fasting: > 95 mg/dl=20
- 1 hr after 100 g oral glucose: ≥ 180 mg/dl=20
- 2 hr after 100 g oral glucose: ≥ 155 mg/dl=20
- 3 hr after 100 g oral glucose: ≥ 140 mg/dl
Random plasma glucose level > 200 mg/dl and/or fasting plasma = glucose=20 >126 mg/dl, confirmed by second test, is also diagnostic

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Best=20 Therapy=20

There are no randomized trials to identify blood glucose targets = to=20 prevent perinatal morbidity, but some evidence supports use of the = following=20 targets:=20
- Fasting capillary blood glucose < 95 mg/dl, 1 hr postprandial = <=20 140 mg/dl, 2 hr postprandial < 120 mg/dl=20
- Focus efforts on women whose fetal abdominal circumference is = ≥ 75th=20 percentile

Blood Glucose Monitoring=20

Self-testing of capillary blood glucose

Lifestyle Measures=20

Nutrition=20
- Weight gain=20
  - Prepregnancy BMI ≥ 30 kg/m²: limit gain to 15 = kg=20
  - Prepregnancy BMI < 18.5 kg/m²: gain of up to 18 = kg=20
  - If desired weight gain achieved by the time of diagnosis, = restrict=20 intake to 25 kcal/kg
- Restrict carbohydrates to 40%=9645% of diet, but ≥ 180 = g/day=20
- Consume complex carbohydrates=20
- Reduce or eliminate monosaccharides, sucrose, and other = oligosaccharides=20 from the diet
Exercise=20
- Assess baseline health and physical capacity=20
- Three exercise sessions per wk, ≥ 15 min each=20
- Improved blood glucose levels may not be seen until regimen has = been=20 maintained for 2=964 wk

Insulin Therapy

Begin if glycemic targets not maintained or if excessive fetal = growth=20 occurs=20
NPH insulin: to control fasting hyperglycemia=20
- 10=9615 units at bedtime=20
- Adjust dose to maintain fasting blood glucose of 60=9690 mg/dl=20
- Measure blood glucose between 2 A.M. and 4 A.M. to assess = nocturnal=20 hypoglycemia
Regular or rapid-action insulin: to control postprandial = hyperglycemia=20
- Use when > 20%=9625% of blood glucose tests register > 140 = mg/dl at=20 1 hr after starting meal or > 120 mg/dl at 2 hr after meal=20
- Inject 1 unit per 10 g anticipated carbohydrate intake=20
- Regular insulin should be taken 40=9660 min before meal; = rapid-action=20 insulin analogues should be taken 0=9615 min before meal=20
- Adjust dose according to postprandial blood glucose levels =
Goals for capillary whole blood glucose levels=20
- Fasting: 60=9690 mg/dl=20
- Preprandial: 60=96105 mg/dl=20
- 1 hr after meal: < 140 mg/dl=20
- 2 hr after meal: < 120 mg/dl=20
- Goals difficult to achieve with current therapeutic tools=20

Oral Antihyperglycemic Agents=20

Glyburide: effective alternative to insulin therapy=20
- Dose: 2.5 mg q.d. initially; increase weekly in 5 mg increments = to=20 maximum of 20 mg q.d. in divided doses or until glycemic control = attained=20
- Monitor glucose levels closely to ensure adequate glycemic = control=20
- Cost/mo: $24
Metformin: safety and efficacy during pregnancy not established =

Follow-Up=20

Measure fasting and/or postprandial blood glucose shortly after = delivery=20 and perform an OGTT at 6 wk postpartum=20
Assess annually for diabetes and metabolic syndrome=20
Perform OGTT before subsequent pregnancies=20
Use appropriate diabetes-prevention measures

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Best = References

Metzger BE, et al: Diabetes Care 21(suppl 2):B161, 1998 [PMID = 9704245]

Crowther CA, et al: N Engl J Med 352:2477, 2005 [PMID 15951574]

Langer O, et al: N Engl J Med 343:1134, 2000 [PMID 11036118]

National Diaetes Education Program

http://www.ndep.nih.gov/diabetes/pubs/NeverTooEarly_Tipsh= eet.pdf

Amy Aronovitz, M.D., has no commercial relationships with = manufacturers of=20 products or providers of services discussed in this module. Boyd E. = Metzger,=20 M.D., is a consultant to Sanofi Aventis.=20

January 2007