Background: Neonatal hyperbilirubinaemia occurs more frequently in Gestational Diabetes Mellitus (GDM), than among normal pregnancies, however this correlation has not been thoroughly investigated in recent literature. The aim of this project was compare maternal and neonatal characteristics from pregnancies complicated by GDM and neonatal hyperbilirubinaemia.
Methods: This was a retrospective clinical audit of pregnancies complicated by GDM under the Macarthur Diabetes Clinic at Campbelltown Hospital between 01/01/2013 and 01/12/2015 using a standard audit sheet and standard clinical definitions. Hyperbilirubinaemia was defined as per NICE guidelines as total serum bilirubin>250 micromol/L at any given gestation. GDM was diagnosed as per ADIPS 1997/2013 guidelines before/after January 2015 respectively.
Results: Births from 652 women with GDM were studied and 30 (4.6%) had births documented as being complicated by neonatal hyperbilirubinaemia (index cases). Of these cases, 20 (66.7%) neonates required phototherapy. Mean age (30.15 ± 0.7 vs 31.93 ± 0.4) and pre-pregnancy body mass index (27.31 ± 0.5 vs 29.83 ± 0.3) were not significantly different, but maternal fasting glucose on oral glucose tolerance test was significantly higher in index cases (5.4±0.1 vs 5.1±0.1 mmol/l; p=0.026) who were also born earlier (36.9±0.5 38.7±0.1 weeks p<0.001) with lower birthweight (2841±127 vs 3312±25g p<0.001). There was also significantly higher incidence of neonatal hypoglycaemia (13.5% vs 2.0% p<0.05) amongst neonates with hyperbilirubinaemia and noted to have a non-significantly lower incidence of insulin treatment (27.38 vs 31.65%).
Conclusions: Significant neonatal hyperbilirubinaemia in pregnancies complicated by GDM is more likely among women with a higher fasting glucose or babies born earlier and/or with lower birthweight. The lower rates of insulin treatment among cases of neonatal hyperbilirubinaemia suggests that stricter glycaemic control may be beneficial in reducing the incidence of neonatal hyperbilirubinaemia. More research is needed to guide practice and reduce the incidence of neonatal hyperbilirubinaemia in GDM.