Classification of Diabetes [1]

• Type 1 diabetes mellitus (T1DM): Inability to produce insulin caused by autoimmune destruction of pancreatic beta cells. T1DM patients have a propensity to develop ketoacidosis. Previously termed insulin-dependent diabetes or juvenile diabetes.
• Type 2 diabetes mellitus (T2DM)   Insulin resistance in muscle and liver with beta-cell failure leading to inadequate insulin secretion . Previously termed noninsulin-dependent diabetes .
• Other: Diabetes due to other specific causes such as cystic fibrosis or drug induced (glucocorticoids).
• Gestational diabetes mellitus (GDM) : Diabetes that was not clearly overt diabetes prior to gestation diagnosed in the second or third trimester of pregnancy.

The American College of Obstetricians and Gynecologists (ACOG)  recommend testing for overt diabetes at the first prenatal visit in overweight or obese (BMI >=25 kg/m2 or >= 23 kg/m2 in Asian Americans) women who have one or more of the following risk factors in table 1 [1,2]

Diagnosis of Overt Dabetes [1]

• Fasting* plasma glucose (FPG) greater than or equal to 7 mmol/L (126 mg/dl )  OR
• Hemoglobin A1 C (A1C) is 6.5% or higher  OR
• Random plasma glucose greater than or equal to 11.1 mmol/L ( 200 mg/dl ) in a patent with symptoms of hyperglycemia or in hyperglycemic crisis. Should be confirmed by FPG or A1C OR
• 2 hour plasma glucose greater than or equal to 11.1 mmol/L (200 mg/dL) during an 75 g OGTT as described by the WHO. Results should be confirmed on repeat testing if hyperglycemia is equivocal .

* Fasting= no caloric intake for at least 8 hours.

The American Diabetes Association (ADA) recommends that women diagnosed with diabetes in the first trimester should be classified as having preexisting pregestational diabetes (type 2 diabetes or, very rarely, type 1 diabetes).

International Association of the Diabetes and Pregnancy Study Groups (IADPSG) representatives issued a statement in 2016 that ".. the use of the IADPSG fasting glucose threshold of ≥5.1 mmol/L (91.8 mg/dL)  for the identification of GDM in early pregnancy is not justified by current evidence ... In contrast to “standard” GDM testing at 24–32 weeks’ gestation, insufficient data exist to confidently recommend cutoff points for oral glucose tolerance testing in early pregnancy (e.g., prior to 20 weeks’ gestation).[3]

The U.S. Preventive Services Task Force recommends all pregnant women,not previously known to have diabetes, be screened for gestational diabetes (GDM) at or beyond 24 weeks of gestation [4] ]

Diagnosis of Gestational Diabetes Mellitus (GDM) [1,2]

The ACOG and ADA support either a 1 step or a 2 step approach for the evaluation of GDM..

1 Step

• 2 Hour (75 g) Oral Glucose Tolerance Test

2 Step

•  1 Hour (50 g) Oral Glucose Tolerance Test
• 3 Hour (100 g) Oral Glucose Tolerance Test
  
  

Diet

Key components in the management of diabetes are diet and exercise.
Click here for diabetic exchange list.

Self-Monitoring of Blood Glucose [1,5]

The ACOG and ADA  recommend initially measuring the fasting blood sugar and either 1 or 2 hours after each meal. The frequency of the monitoring may be modified in gestational diabetes (GDM) once glucose levels have been well controlled on diet [1].

Example of a prescription for glucose test strips :

Name of Blood Glucose Strip
Use (4 to 10) of strips per day
# 200 strips
Refills: 6 months
Patient is pregnant

• Fasting less than or equal to 95 mg/dL (5.3 mmol/L)  AND EITHER
• One-hour postprandial less than or equal to 140 mg/dL (7.8 mmol/L) OR 
• Two-hour postprandial less than or equal to 120 mg/dL (6.7 mmol/L)

Women with pregestational diabnetes should check urine ketones if their glucose levels routinely exceed 200 mg/dL and immediately report positive results to their health care teams” [6]

• Insulin is the preferred medication for treating hyperglycemia in all pregnant women with diabetes mellitus as it does not cross the placenta. All oral agents cross the placenta and lack long-term safety data [2,5].
• Regular insulin, insulin lispro, aspart, NPH, insulin glargine, and insulin detemir are all acceptable for use in pregnancy [2].
• Women with gestational dabetes who refuse insulin therapy , who may be unable to safely administer insulin, or who cannot afford insulin ACOG advises metformin (and rarely glyburide) is a reasonable alternative choice to insulin [2]

Insulin

Synthetic "human" insulin is manufactured using recombinant DNA technology.  Doses of insulin are measured in units. U-100 insulin contains 100 units/mL. The most commonly used types of insulin during pregnancy are regular insulin and NPH.  Neutral Protamine Hagedorn , NPH, is named after one of its developers the physician Hans Christian Hagedorn who discovered that combining a suspension of crystalline zinc insulin with protamine could prolong the duration of action of the insulin.  Insulin aspart , insulin lispro, insulin detemir, and insulin glargine are human insulin that have had their chemical composition slightly altered to influence their onset and duration of action. Allergy to recombinant human insulin preparations is uncommon , and more likely due to components including zinc, protamine, and meta-cresol [8].

Give calculated dose alone .Do not dilute or mix with any other insulin or solution. Do not administer subcutaneously via an insulin pump, intramuscularly, or intravenously.

If changing patients from once-daily NPH insulin to once-daily LANTUS, the recommended initial LANTUS dose is the same as the dose of NPH that is being discontinued.

& If changing patients from twice-daily NPH insulin to once-daily LANTUS, the recommended initial LANTUS dosage is 80% of the total NPH dose that is being discontinued. This dosage reduction will lower the likelihood of hypoglycemia

(Injection: 100 units per mL of insulin glargine. LANTUS is available as: 10 mL multiple-dose vial - 3 mL single-patient-use SoloStar prefilled pen )

Insulin detemir [rDNA origin] injection Levemir ®

Insulin .Onset 1 to 3 hours, peak of action 4 to 14 hours (no true peak), duration of action 6 to 23 hours (dose dependent) [11]