[Gestational diabetes mellitus. Experience at a third level hospital].
BACKGROUND
The prevalence of type 2 diabetes mellitus and of gestational diabetes mellitus is high in the Mexican population; thus, strategies to improve its detection and prevent obstetric and perinatal complications are essential.


METHODS
During the period 2000-2004 a total of 8,074 pregnant women were studied from the day of performance, 50-g, 1 hour glucose screening test for gestational diabetes mellitus (ST-GDM) until the end of pregnancy using the same protocol: ST-GDM was performed immediately after 14 weeks of gestation in high-risk women and between 24-28 weeks in those with regular risk. Two weeks later 100-g, 3 hour oral glucose tolerance test (3h-OGTT) was performed in women with ST-GDM [symbol: see text] 130 but < 180 mg/dL, and patients were classified according to Freinkel's criteria in class A1, A2 and B1 gestational diabetes mellitus. All women received a diet according to their ideal weight for gestational age and, when necessary, insulin was added to achieve an adequate glycemic control.


RESULTS
From 8,074 glucose screening tests for gestational diabetes mellitus, 37.2% (n = 2,997) were positive and 17.2% (n = 514) diagnostic for gestational diabetes mellitus (serum glucose [symbol: see text] 180 mg/dL). In 2,483 patients, ST-GDM was positive but negative for gestational diabetes (serum glucose >130 but <180 mg/dL); in 1,070 of them (43.0%) gestational diabetes mellitus was diagnosed by means of 3h-OGTT. The diagnosis of class A1 gestational diabetes mellitus was done in 908 patients (84.9%), A2 in 188 (11.8%) and B1 in 51 (3.2%). Patients with gestational diabetes diagnosed only by an abnormal ST-GDM were classified as class A1 gestational diabetes mellitus. Gestational age at diagnosis by ST-GDM was 12.4 +/- 4.7 weeks and 27.4 +/- 5.8 weeks when diagnosed by a 3h-OGTT. The total daily dose of insulin required was related to Freinkel's classification: 16.0% (n = 215/1,345) with class A1 gestational diabetes mellitus required 0.48 +/- 0.33 U/day/kg and 85.0% (n = 43/51) with class B1 needed 1.0 +/- 0.32 U/day/kg at the end of pregnancy, which occurred at 38.2 +/- 2.0 weeks in all 3 groups. In decreasing order of occurrence perinatal complications were: pregnancy-induced hypertension (specially in class B1 gestational diabetes mellitus), urinary tract infections and premature rupture of membranes. Birth weights either < 2,500 g or > 4,000 g were more frequent among women with class B1 gestational diabetes, than in the other 2 groups. After pregnancy ended (6-8 weeks), 52.2% of women with gestational diabetes (mostly class B1) was diagnosed with permanent type 2 diabetes mellitus.


CONCLUSIONS
In this study the percentage of pregnant women diagnosed as having gestational diabetes mellitus exclusively by ST-GDM was high (17.2%). Freinkel's classification of such disease predicted higher risk in women with class B1 gestational diabetes mellitus for: 1) obstetric complications, 2) higher doses of insulin to achieve an adequate glycemic control; 3) newborns' birth weight < 2,500 g or > 4,000 g for gestational age, 4) having type 2 diabetes mellitus in late puerperium.
Ramírez Torres
María Aurora
MA
Departamento de Endocrinología, Instituto Nacional de Perinatología, colonía Lomas Virreyes, México. maurorat@hotmail.com
D000328:Adult; D016640:Diabetes, Gestational / Q000175:diagnosis*; D005260:Female; D006801:Humans; D011247:Pregnancy; D011446:Prospective Studies