Reclassification of maternal glycemic status should be performed at least 6 weeks after delivery and according to the guidelines of the “Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus”.
If glucose levels are normal post-partum, reassessment of glycemia should be undertaken at a minimum of 3-year intervals. Women with IFG or IGT in the postpartum period should be tested for diabetes annually; these patients should receive intensive MNT and should be placed on an individualized exercise program because of their very high risk for development of diabetes. All patients with prior GDM should be educated regarding lifestyle modifications that lessen insulin resistance, including maintenance of normal body weight through MNT and physical activity. Medications that worsen insulin resistance (e.g., glucocorticoids, nicotinic acid) should be avoided if possible. Patients should be advised to seek medical attention if they develop symptoms suggestive of hyperglycemia. Education should also include the need for family planning to assure optimal glycemic regulation from the start of any subsequent pregnancy. Low-dose estrogen-progestogen oral contraceptives may be used in women with prior histories of GDM, as long as no medical contraindications exist.
Therapeutic strategies during pregnancy
Monitoring
- Maternal metabolic surveillance should be directed at detecting hyperglycemia severe enough to increase risks to the fetus. Daily self-monitoring of blood glucose (SMBG) appears to be superior to intermittent office monitoring of plasma glucose. For women treated with insulin, limited evidence indicates that postprandial monitoring is superior to preprandial monitoring. However, the success of either approach depends on the glycemic targets that are set and achieved.
- Urine glucose monitoring is not useful in GDM. Urine ketone monitoring may be useful in detecting insufficient caloric or carbohydrate intake in women treated with calorie restriction.
- Maternal surveillance should include blood pressure and urine protein monitoring to detect hypertensive disorders.
- Increased surveillance for pregnancies at risk for fetal demise is appropriate, particularly when fasting glucose levels exceed 105 mg/dl (5.8 mmol/l) or pregnancy progresses past term. The initiation, frequency, and specific techniques used to assess fetal well-being will depend on the cumulative risk the fetus bears from GDM and any other medical/obstetric conditions present.
- Assessment for asymmetric fetal growth by ultrasonography, particularly in early third trimester, may aid in identifying fetuses that can benefit from maternal insulin therapy (see below).
Management
- All women with GDM should receive nutritional counseling, by a registered dietitian when possible, consistent with the recommendations by the American Diabetes Association. Individualization of medical nutrition therapy (MNT) depending on maternal weight and height is recommended. MNT should include the provision of adequate calories and nutrients to meet the needs of pregnancy and should be consistent with the maternal blood glucose goals that have been established. Noncaloric sweeteners may be used in moderation.
- For obese women (BMI >30 kg/m2), a 30??ecent research from Brazil, “The capacity to increase glomerular filtration rate in response to an acute oral protein load is known as the renal functional reserve; the loss of such capacity is used as a marker of hyperfiltration. This physiological response in obese hypertensives is not yet fully understood.” I.M.D. Pecly and colleagues working with the Hypertension Clinic aimed “to study the interdependent effects of obesity and hypertension on renal reserve, taking into account renal kallikrein and nitric oxide in the modulation of that parameter.” They explained, “Fourteen obese hypertensives (mean age, 50.5? first 3 months following surgery. Both operations generated similar changes in HOMA IR, although postoperative HOMA IR levels were significantly lower after LRYGBR. These findings suggest that caloric restriction plays a significant role in improving insulin resistance after both LAGB and LRYGBP.” Ballantyne and colleagues published the results of their research in Obesity Surgery (Short-term changes in insulin resistance following weight loss surgery for morbid obesity: Laparoscopic adjustable gastric banding versus laparoscopic Roux-en-Y gastric bypass. Obes Surg, 2006;16(9):1189-1197). For additional information, contact G.H. Ballantyne, Hackensack University, Medical Center, Sect Minimally Invas & Telerobot Surgery, Suite 901, 20 Prospect Avenue, Hackensack, NJ 07601, USA.
