Neonatal and obstetric outcomes in diet- and insulin-treated women with gestational diabetes mellitus: a retrospective study

BACKGROUND: To evaluate the neonatal and obstetric outcomes of pregnancies complicated by gestational diabetes mellitus (GDM). Screening and treatment – diet-only versus additional insulin therapy – were based on the 2010 national Dutch guidelines. METHODS: Retrospective study of the electronic medical files of 820 singleton GDM pregnancies treated between January 2011 and September 2014 in a university and non-university hospital. Pregnancy outcomes were compared between regular care treatment regimens –diet-only versus additional insulin therapy- and pregnancy outcomes of the Northern region of the Netherlands served as a reference population. RESULTS: A total of 460 women (56 %) met glycaemic control on diet-only and 360 women (44 %) required additional insulin therapy. Between the groups, there were no differences in perinatal complications (mortality, birth trauma, hyperbilirubinaemia, hypoglycaemia), small for gestational age, large for gestational age (LGA), neonate weighing >4200 g, neonate weighing ≥4500 g, Apgar score <7 at 5 min, respiratory support, preterm delivery, and admission to the neonatology department. Neonates born in the insulin-group had a lower birth weight compared with the diet-group (3364 vs. 3467 g, p = 0.005) and a lower gestational age at birth (p = 0.001). However, birth weight was not different between the groups when expressed in percentiles, adjusted for gestational age, gender, parity, and ethnicity. The occurrence of preeclampsia and gestational hypertension was comparable between the groups. In the insulin-group, labour was more often induced and more planned caesarean sections were performed (p = 0.001). Compared with the general obstetric population, the percentage of LGA neonates was higher in the GDM population (11.0 % vs.19.9 %, p = <0.001). CONCLUSIONS: Neonatal and obstetric outcomes were comparable either with diet-only or additional insulin therapy. However, compared with the general obstetric population, the incidence of LGA neonates was significantly increased in this GDM cohort.