[Comparison between two gestational diabetes screening tests and the perinatal outcome].

Purpose: To compare two screening tests for diabetes and their results to pregnancy outcomes.

Methods: In total, 279 pregnant women were submitted to two screening tests for gestational diabetes--fasting glycemia plus risk factors (FG + RF) and to the simplified glucose tolerance test (GTT50g). Screening by FG + RF consisted of the determination of fasting glycemia and anamnesis for the identification of risk factors on the occasion of the first prenatal visit. The GTT50g was performed between the 24th and the 28th week of pregnancy and consisted of the determination of plasma glycemia under fasting conditions and one hour after an oral overload with 50 g glucose. Positive and negative results were compared to pregnancy outcome. The dependent variables were: type of delivery, gestational age, weight and ponderal index at birth, Apgar indexes <7 in the 1st and 5th minutes, need for admission to the Intensive Care Unit (ICU), duration of hospitalization, and neonatal death. Data were analyzed statistically through the Students t-test, and the level of significance was set at 5%.

Results: Only two of the perinatal variables studied were distinguished by the tests. An abnormal GTT50g was associated with a greater proportion of cesarean deliveries (58.7 versus 34.3%) and a positive FG + RF association was related to a higher rate of premature births (15.4 versus 5.4%). The other dependent variables did not differ among patients with positive and negative results of the two screening tests.

Conclusions: Despite the relation between prematurity and a positive FG + RF association, the increase of caesarean sections and the abnormal GTT50g, it would be a critical failure to accept these associations as definitive. Among others explanations, multiple intercurrent factors and the characteristics of the screening tests themselves should be considered.