Gestational glucose intolerance and pregnancy outcomes: a retrospective study in the primary care setting of Macau

Although glucose intolerance is prevalent in Macau, it is rarely assessed during pregnancy. This study examined short-term maternal and neonatal outcomes at different maternal glucose levels in Macau. A total of 2388 pregnant women who received antenatal care at Health Centers and delivered at the Centro Hospitalar Conde de São Januário between June 2018 and December 2019 were included in this study. Gestational diabetes mellitus (GDM) was diagnosed using Carpenter and Coustan criteria, involving a 50 g glucose challenge test (GCT) followed by a 100g oral glucose tolerance test (OGTT). Participants were categorized into 4 groups: normal glucose tolerance if GCT was negative; mild gestational hyperglycemia in this study if positive GCT without GDM; GDM patients with normal fasting blood glucose (FBG) or high FBG in OGTT. Logistic regression analysis was employed to compare pregnancy outcomes among these 4 groups. Due to the limited number of cases, we combined several adverse maternal outcomes, including pregnancy-induced hypertension, assisted delivery, primary Caesarean section, moderate to severe perineal trauma, and postpartum hemorrhage, into a composite measure. The results showed higher rates of the aforementioned outcomes for mild gestational hyperglycemia and GDM with high FBG in OGTT groups [adjusted odds ratio (aOR) 1.32, 95% confidence interval (CI) 1.06-1.64; aOR 2.04, 95% CI 1.24-3.37], as well as macrosomia risk (aOR 2.02, 95% CI 1.11-3.66; aOR 5.04, 95% CI 2.03-12.52) and large-for-gestational age infants (aOR 1.48, 95% CI 1.02-2.16; aOR 4.34, 95% CI 2.31-8.15). Pregnancy outcomes were similar for normal glucose tolerance and GDM with normal FBG in OGTT. Mild gestational hyperglycemia raised the likelihood of adverse maternal outcomes and excessive infant birth weights. Even after achieving target glucose levels, GDM patients with elevated fasting glucose readings in OGTT remained at significant risk for these events. Instead, fasting normoglycemic GDM was treated effectively at Macau Health Centers.