Early screening for gestational diabetes mellitus is not associated with improved pregnancy outcomes: an observational study including 9795 women.

AIMS: In addition to screening for hyperglycaemia during pregnancy after 24 weeks of gestation (WG), the current guidelines also suggest screening in early pregnancy and referring women with early gestational diabetes mellitus (eGDM) or overt diabetes (OD) for immediate care. Our aim was to evaluate this strategy. METHODS: This study evaluated, at our hospital (2012-2016), whether the incidence of a predefined composite outcome (preeclampsia, large-for-gestational-age infant, shoulder dystocia) and secondary outcomes was different when women were screened only after 22WG ('late screening only') or before 22WG and treated for eGDM or OD if present, with repeat screening after 22WG if absent ('early ± late screening'). RESULTS: Early ± late screening (n = 4605, 47.0%) increased between 2012 and 2016 (P < 0.0001) and was associated with more risk factors for GDM than late screening only. Glycaemic status differed in both groups (early ± late screening: eGDM 10.3%, GDM 12.1%, OD 0.9% vs. late screening only: GDM 16.8%, OD 1.2%; P < 0.001), with a higher rate of insulin therapy (8.9% vs. 6.0%; P < 0.001) and less gestational weight gain (11.1 ± 5.4 kg vs. 11.4 ± 5.5 kg; P = 0.013) in the early ± late screening group. Rates of those meeting the composite criterion were similar in both groups [11.6% vs. 12.0%, respectively; odds ratio (OR): 1.040, 95% confidence interval (CI): 0.920-1.176; P = 0.53] and remained comparable after adjusting for Propensity Scores (OR: 1.046, 95% CI: 0.924-1.185; P = 0.4790). Rates for secondary outcomes were also similar in both groups. CONCLUSION: While a strategy including early measurement of fasting plasma glucose during pregnancy increases the incidence and care of hyperglycaemia during pregnancy, it may not significantly improve pregnancy outcomes.