ABSTRACT
Gestational diabetes mellitus (GDM) is a frequent medical complication during pregnancy. Screening and diagnostic practices for GDM are inconsistent across the world. This narrative review includes data from 87 observational studies and randomized controlled trials (RCTs), and aims to give an overview of the current evidence on screening strategies and diagnostic criteria for GDM. Screening in early pregnancy remains controversial and studies show conflicting results on the benefit of screening and treatment of GDM in early pregnancy. Implementing the one-step "International Association of Diabetes and Pregnancy Study Groups" (IADPSG) screening strategy at 24-28 weeks often leads to a substantial increase in the prevalence of GDM, without conclusive evidence regarding the benefits on pregnancy outcomes compared to a two-step screening strategy with a glucose challenge test (GCT). In addition, RCTs are needed to investigate the impact of treatment of GDM diagnosed with IADPSG criteria on long-term maternal and childhood outcomes. Selective screening using a risk-factor-based approach could be helpful in simplifying the screening algorithm but carries the risk of missing significant proportions of GDM cases. A two-step screening method with a 50g GCT and subsequently a 75g oral glucose tolerance test (OGTT) with IADPSG could be an alternative to reduce the need for an OGTT. However, to have an acceptable sensitivity to screen for GDM with the IADPSG criteria, the threshold of the GCT should be lowered from 7.8 to 7.2 mmol/L. A pragmatic approach to screen for GDM can be implemented during the COVID-19 pandemic, using fasting plasma glucose (FPG), HbA1c or even random plasma glucose (RPG) to reduce the number of OGTTs needed. However, usual guidelines and care should be resumed as soon as the COVID pandemic is controlled.
ABSTRACT
AIMS: To determine impact of mild fasting hyperglycemia in early pregnancy (fasting plasma glucose [FPG] 5.1-5.5 mmol/L) on pregnancy outcomes. METHODS: We measured FPG at 11.9 ± 1.8 weeks in 2006 women from a prospective cohort study. Women with FPG ≥5.6 mmol/L (19) received treatment and were excluded from further analyses. A total of 1838 women with FPG <5.6 mmol/L received a 75 g oral glucose tolerance test (OGTT) between 24 and 28 weeks of pregnancy. RESULTS: Of all participants, 78 (4.2%) had FPG 5.1 to 5.5 mmol/L in early pregnancy, of which 49 had a normal OGTT later in pregnancy (high fasting normal glucose tolerance [NGT] group). Compared with the NGT group with FPG <5.1 mmol/L in early pregnancy (low fasting NGT group, n = 1560), the high fasting NGT group had a higher body mass index (BMI), higher insulin resistance with more impaired insulin secretion and higher FPG and 30 minute glucose levels on the OGTT. The admission rate to neonatal intensive care unit (NICU) was significantly higher in the high fasting NGT group than in the low fasting NGT group (20.4% [10] vs 9.3% [143], P = .009), with no difference in duration (7.0 ± 8.6 vs 8.4 ± 14.3 days, P = .849) or indication for NICU admission between both groups. The admission rate to NICU remained significantly higher (odds ratio 2.47; 95% confidence interval 1.18-5.19, P = .017) after adjustment for age, BMI, and glucose levels at the OGTT. CONCLUSIONS: When provision of an OGTT is limited such as in the Covid-19 pandemic, using FPG in early pregnancy could be an easy alternative to determine who is at increased risk for adverse pregnancy outcomes.