The prevalence of Gestational Diabetes mellitus (GDM) is growing worldwide. 1-14% of women in pregnancy is affected by DM 1. Due to increased incidence and proposed lower¬ing of the thresholds for diagnosis the health care cost of GDM can be expected to rise proportionately. The discussion of whether a benefit exists to the treatment of GDM assumes greater importance now than in the past.
Even though it has long been known that women with preexisting type 1 and type 2 diabetes are at increased risk for adverse maternal and fetal outcomes, the relationship of GDM to various perinatal risks has been less clear. O'Sullivan and Mahan3 developed, Glucose tolerance test criteria for the diagnosis of GDM, nearly 50 years ago. It has been known that, if optimal care is not provided, women with GDM and elevated fast¬ing glucose levels appear to be at risk for fetal overgrowth and perinatal morbidity.4
For several decades whether a significant association of milder forms of carbohydrate intolerance exists with macrosomia and adverse perinatal outcomes has been questioned and debated.5 Older studies, focusing on this issue interpreted that confounding variables including parity and maternal obesity may not have been considered in the analyses or that treatment was in fact applied to the population described.6 . Therefore, the effect of glycemia on various outcomes may have been incorrectly estimated.
The recent Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study has settled much of the debate about the relationship of various degrees of maternal glycemia to specific pregnancy outcomes.7 In this large-scale international study, women with fasting glucose up to 105 mg/dL, were enrolled. The researchers described the continuous association between maternal glucose concentrations (utilizing a 75 g blinded 2 hour OGTT) and increasing birth weight, cord blood serum C-peptide levels and other adverse pregnancy outcomes. These associations were present at glucose levels currently lower than those used to diagnose GDM. 7
In spite of little evidence to support a treatment benefit to the identification and treatment of mild carbohydrate intolerance during pregnancy screening for GDM has been recommended for most pregnant women 8 Universal screening for GDM has been adopted by most US obstetricians for nearly 15 years.9 However, lack of international consensus regarding diagnostic criteria has continued to add to the problem of assessing the value of treatment. Currently a 3 hour 100 g diagnostic test is utilized predominantly in the United States, while much of the world uses a 75 g, 2 hour test.
The 2008 guidelines of the US Preventive Services Task Force concluded that there is lack of evidence to evaluate the benefits and harms of screening and treatment of GDM. 11 Recently, 8 ran¬domized trials concerning treatment of GDM were identified.12 The conclusion was that, women with GDM should be considered only for specific treatment in...