Objective: To determine the impact of 3-day intensive dietary therapy during admission on glycemic control.
Material and Method: GDM women, with level of fasting blood glucose (FBS) at or above 105 mg/dl on their oral glucose tolerance test (OGTT), were hospitalized. After 3-day intensive dietary therapy, the women were stratified by FBS value and mean 2-hour postprandial blood glucose. Those with poor glycemic control, FBS at or above 105 mg/dl, were prescribed insulin therapy.
Result: Between 1 August 2001 to 31 December 2002, a total of 9861 pregnant women were screened for clinical risk factors of GDM at their first antenatal visits, and 4663 had at least 1 risk. After 50-gm glucose challenge test and 100-gm OGTT, GDM was diagnosed in 300 women. Only 18% (54 in 300 cases) of GDM had level of FBS at or above 105 mg/dl on OGTT. They were admitted in a special ward for further investigation and initial management. After 3 days of intensive dietary therapy, the FBS and mean 2-hour postprandial blood glucose level were monitored and stratified in 3 groups. Only 42.6% of admission group (23 in 54 cases) still had FBS at or above 105 mg/dl and required insulin therapy (group 1). One third (18 in 54 cases) could avoid insulin therapy due to the level of FBS below 105 mg/dl and mean 2- hour postprandial blood glucose below 120 mg/dl (group 2). This second group was discharged, and due to attend the high risk pregnancy clinic a few weeks later. The third group (group 3), comprising one fourth (13 in 54 cases), had FBS below 105 mg/dl but had a mean 2-hour postprandial blood glucose at or above 120 mg/dl. This third group were also discharged and were monitored glycemic profile by FBS and 2-hour postprandial blood
glucose every time during their visits to the high risk pregnancy clinic. According to criteria of 2-hour postprandial blood glucose at or above 120 mg/dl on two or more occasions within a 1-2 weeks interval, no one in group 3 needed insulin therapy afterward.
Conclusion: GDM women with FBS at or above 105 mg/dl on their OGTT, should be prescribed intensive dietary therapy alone for 3 days inside hospital rather than initiating insulin immediately after diagnosis. One third had a benefit of avoiding insulin therapy. Only 42% failed to achieve good glycemic control and still needed insulin therapy. One fourth showed optimal glycemic control after this intervention (FBS below 105 mg/dl) but had mean 2-hour postprandial blood glucose at or above 120 mg/dl. Longer trial of dietary therapy should be considered in this last group to avoid over treatment of insulin therapy.

Keywords: Gestational diabetes mellitus, Intensive dietary therapy, Insulin therapy