Association between maternal glucose levels during pregnancy and gestational diabetes mellitus: an analytical cross-sectional study.

Abstract

BackgroundTo evaluate the association between fasting glucose levels in women throughout pregnancy and the occurrence of gestational diabetes mellitus (GDM) and other pregnancy complications, macrosomia, and cesarean delivery.MethodsAn analytical cross-sectional study with 829 healthy pregnant women receiving health care at a public maternity unit in Rio de Janeiro between 1999 and 2008. The dependent variables assessed in the study were: GDM (was confirmed when two or more values were above the glucose curve using 100 g glucose), complications, mode of delivery and birth weight. Macrosomia was defined as a birth weight of >4000 g. The independent variables assessed were: maternal fasting glucose per trimester as a continuous variable, divided into three categories, socio-demographic data on the mothers. The level of statistical significance was set at 5%.ResultsThe mean fasting glucose levels of the women who had GDM were higher in the second trimester than for those who had no pregnancy complications (90.5 mg/dL vs. 78.5 mg/dL, p = 0.000). Higher mean fasting glucose levels were also found in the third trimester for women who developed GDM than for those with no pregnancy complications (90 mg/dL vs. 77.8 mg/dL, p = 0.016). Women who had a cesarean delivery had higher fasting glucose levels in the second (80.4 mg/dL vs. 78 mg/dL, post hoc = 0.034) and third (80.4 mg/dL and 77.1 mg/dL; post hoc = 0.005) trimesters than women who had a normal delivery. Also, higher fasting glucose levels were found in the second semester for women whose infants had macrosomia than for women whose newborns were normal weight (86.2 mg/dL and 78.8 mg/dL; post hoc = 0.003). The chance of develop GDM was higher for the women with glucose levels in the 90–94 mg/dL range in the second trimester (OR = 7.2; 95% CI = 2.33-22.24) than for the women whose glucose levels were in the <80 mg/dL and 80-90 mg/dL ranges.ConclusionSecond and third trimester fasting glucose levels below the cut-off values for the diagnosis of GDM are associated with an increased risk of pregnancy complications. The dependent variables assessed in the study were: GDM (present/absent), complications, mode of delivery (normal, forceps, cesarean), and birth weight.