Gestational diabetes mellitus and adverse pregnancy outcomes: The impact of different treatment targets at two major Australian maternity services.

Objective: There is insufficient evidence for treatment targets in Gestational Diabetes Mellitus (GDM). We aimed to explore the impact of different treatment targets on pregnancy outcomes. Method(s): An observational study was conducted of singleton births >20 weeks at Monash Health (MH) and Royal Women's Hospital (RWH) from 2009-2013. Data (pregnancy details, maternal and neonatal outcomes) were obtained from each hospital's pregnancy database. Outcomes for women with GDM at MH (n = 2891) and RWH (n = 1930) were compared [diagnosis: 2 h 75 g OGTT at 24-28 weeks with fasting glucose >=5.5 mmol/L and/or 2 h >= 8.0 mmol/L]. Each hospital follows a similar GDM management protocol but applies different treatment targets: MH fasting <5.5 mmol/L, 2 h post-prandial <7.0 mmol/L; RWH fasting <5.0 mmol/L, 2 h < 6.7 mmol/L. Descriptive statistics are presented. Multivariable regression analysis will be used to examine associations between GDM treatment and adverse outcomes. Result(s): The prevalence of GDM and requirement for insulin at MH were 7.9% and 31%, and at RWH with stricter treatment targets were 6.3% and 47% respectively. Over half of women with GDM were overweight or obese. The rate of special care nursery admission (29.6% vs 17.0%) was higher at MH compared to RWH, but rates of induction of labour (30.6% vs 56.6%) and caesarean section (33.8% vs 39.5%) were lower (all p < 0.001), partly reflecting hospital protocols. Babies of women with GDM were born later (mean gestation 39 +/- 2 vs 38 +/- 2 wk, p < 0.001) at MH compared to RWH, and had higher rates of respiratory distress (3.6% vs 1.2%, p < 0.001), hypoglycaemia (9.9% vs 2.2%, p < 0.001) and macrosomia (11.3% vs 9.5%, p = 0.035), but lower rates of pre-term birth (8.5% vs 11.3%, p = 0.001) and stillbirth (0.3% vs 0.7%, p = 0.024). Rates of shoulder dystocia and jaundice were comparable. Conclusion(s): Stricter treatment targets for GDM appear to reduce macrosomia, without increasing neonatal hypoglycaemia or spe