Dr. Mohsena Iqbal :
Gestational Diabetes Mellitus (GDM) is as any degree of glucose intolerance with onset or first recognition during pregnancy. Whether insulin or only diet modification is applied for treatment and whether or not the condition persists after pregnancy, which doesn’t rule out the likelihood that unrecognized glucose intolerance can have antedated with the pregnancy.
Approximately 7% of all pregnancies are complicated by GDM, leading to about 200,000 cases annually. The prevalence may range from 1 to 14% of all pregnancies, counting on the population studied and therefore the diagnostic tests employed.
Risk assessment for GDM should be undertaken at the earliest prenatal visit. Women with clinical characteristics according to a high risk of GDM (marked obesity, personal history of GDM, glycosuria, or a robust case history of diabetes) should undergo glucose testing as soon as feasible. If they’re found to not have GDM at that initial screening, they ought to be retested between 24 and 28 weeks of gestation. Patients of mean risk should have testing undertaken at 24-28 weeks of gestation. Low-risk status requires no glucose testing, but this category is restricted to those women meeting all of the subsequent characteristics: 1) Age <25 years, 2) Weight normal before pregnancy, 3) Member of an ethnic group with a low prevalence of GDM, 4) No known diabetes in first-degree relatives, 5) No history of abnormal glucose tolerance, 6) No history of poor obstetric outcome.
A fasting plasma glucose level >126 mg/dl (7.0 mmol/l) or a casual plasma glucose >200 mg/dl (11.1 mmol/l) meets the threshold for the diagnosis of diabetes, if confirmed on a subsequent day, and precludes the need for any glucose challenge. The nonappearance of this percentage of hyperglycaemia, evaluation for GDM in women with average or high-risk characteristics should follow one among two approaches.
One-step approach is diagnosis of oral glucose tolerance test without prior plasma or serum glucose screening. The one-step approach could also be cost-effective in high-risk patients and two-step approach includes when performing a primary screening by measuring the plasma or serum glucose concentration 1 h after a 50-g oral glucose load (glucose challenge test [GCT]) and perform a diagnostic OGTT on that subset of ladies exceeding the glucose threshold value on the GCT. When the two-step approach is applied, glucose threshold value >140 mg/dl (7.8 mmol/l) identifies roughly 80% of patient with GDM, and the yield is further increased to 90% by using a cut off of >130 mg/dl (7.2 mmol/l) either approach, the diagnosis of GDM is based on an OGTT.
The way of monitoring the pregnant mother is A) Maternal metabolic surveillance should be directed at detecting hyperglycaemia severe enough to increase risks to the foetus. Regular self-monitoring of blood sugar (SMBG) appears to be increase to intermittent monitoring of plasma glucose. For ladies treated with insulin, lean evidence indicates that postprandial monitoring is superior to pre-prandial monitoring. B) Urine glucose monitoring isn’t useful in GDM. In urine ketone monitoring can be essential in detecting inadequate caloric or carbohydrate intake in female treated with calorie restriction. C) Maternal surveillance should include vital signs and urine protein monitoring to detect hypertensive disorders. D) Increased surveillance for pregnancies in danger for foetal demise is acceptable, 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 fatal well-being will depend on the cumulative risk the foetus bears from GDM and any other medical/obstetric conditions present. E) Assessment for asymmetric fatal growth by ultrasonography, particularly in early third trimester, may aid in identifying foetuses that can benefit from maternal insulin therapy (see below).
All women with GDM should receive nutritional counselling, by a registered dietitian, when possible, consistent with the recommendations by the American Diabetes Association. Personalization of medical nutrition therapy (MNT) depending on maternal weight and height is recommended.
For obese female patient (BMI >30 kg/m2), a 30-33% calorie restriction (to ~25 kcal/kg actual weight per day) has been shown to decreasehyperglycaemia and plasma triglycerides with no increase in ketonuria. Restriction of carbohydrate intake should be mandatory.
Insulin is the pharmacologic therapy that has most consistently been shown to reduce fatal morbidities when added to MNT. Selection of pregnancies for insulin therapy is often supported on measures of maternal glycemia with or without assessment of fatal growth characteristics.
Fasting whole blood glucose level is =95 mg/dl (5.3 mmol/l) and Fasting plasma glucose level is =105 mg/dl (5.8 mmol/l).
Measurement of the fatal abdominal circumference early in the third trimester can identify a large subset of infants with no excess risk of macrosomia in the absence of maternal insulin therapy. This point of view has been tested firstly in pregnancies with maternal fasting serum glucose levels <105 mg/dl (5.8 mmol/l). Human insulin should be used when insulin is prescribed, and SMBG should guide the doses and timing of the insulin regimen. The use of insulin analogy has not been adequately tested in GDM.
Oral glucose-lowering agents have generally not been recommended during pregnancy. However, one randomized, unblinded clinical trial compared the use of insulin and glyburide in women with GDM who were not able to meet glycaemic goals on MNT. Programs of moderate physical exercise have been shown to lower maternal glucose concentrations in women with GDM, although the impact of exercise on neonatal complications awaits rigorous clinical trials.
GDM is not of itself an indication for caesarean delivery or for delivery before 38 completed weeks of gestation. Prolongation of gestation past 38 weeks increases the risk of fatal macrosomia without reducing caesarean rates, so that delivery during the 38th week is recommended unless obstetric considerations dictate otherwise. Breast-feeding, as always, should be encouraged in women with GDM.
(Dr. Mohsena is Consultant Diabetic & Endocrinology serving in Malaysia).
