The Risk Stratification of Women with Gestational Diabetes: Can we predict adverse pregnancy outcomes?

Abstract

Background: Risk informed models of care are critical to addressing the workload for diabetes services with the rising prevalence of Gestational Diabetes (GDM) Aim: To explore the effect of glycaemic, weight and non-glycaemic/weight related factors on the risk of adverse pregnancy outcomes Methods: Data was obtained from 11,011 singleton pregnancies at Bankstown-Lidcombe Hospital from 2010-2015. Outcomes included the incidence of pre-eclampsia, prematurity, induction of labour, caesarean section, low birthweight, SGA (<10thcentile), macrosomia, LGA (>90thcentile), Apgar scores and neonatal ICU admissions. Birthweight centiles were calculated using the customised calculator. Outcomes were assessed in women in fasting glucose 5.1-5.4mmol/L (IADPSG-GDM) compared to normal glucose tolerant women (NGT) and ADIPS1998-GDM versus NGT women. In another dataset of 3095 singleton GDM pregnancies from 1992-2013, outcomes were assessed in women with GWG below, according to or above the Institute of Medicine (IOM) targets. Modifying these targets was evaluated. Risk prediction models and calculators for adverse pregnancy outcomes were formulated to integrate non-glycaemic and non-weight related variables. Results: Women with fasting glucose between 5.1-5.4mmol/L were at a two-fold risk of LGA compared to women with NGT, thus supporting the new IADPSG criteria change. Treatment of GDM reduced maternal GWG and attenuated the risk of LGA Excessive GWG above IOM, resulted in increased rates of LGA, macrosomia and caesarean section. Modifying the IOM weight gain targets did not attenuate adverse outcomes. Finally, a number of non-glycaemic factors were associated with adverse pregnancy outcomes in GDM and were integrated into a risk prediction model. This thesis also presents a proposed risk informed model of care. Conclusion: A combination of glycaemic, weight gain and non-glycaemic/non-weight related factors could be used to predict the risk of adverse outcomes in GDM pregnancies.