Impact of type 2 diabetes, obesity and glycaemic control on pregnancy outcomes

Background: There are no contemporary cohorts examining pregnancy outcomes in women with type 2 diabetes (T2D) in Australia. Aim: To compare pregnancy outcomes in women with and without T2D, and assess effects of body mass index (BMI) and glycaemic control on outcomes. Materials and methods: An historical cohort study was conducted of all singleton births > 20 weeks gestation at a specialist maternity network in Australia from 2010 to 2013. Data were extracted from the Birthing Outcomes System database. Multivariable logistic regression analysis was used to examine associations between presence of T2D and pregnancy outcomes. Results: Outcomes for 138 pregnancies with T2D and 27 075 pregnancies in women without diabetes were compared (type 1 diabetes and gestational diabetes excluded). Women with T2D were older and more overweight compared to women without diabetes (P < 0.01). Their babies were born earlier (P < 0.01) with increased risk of large for gestational age (adjusted odds ratio 2.13 (95% CI 1.37-3.32)), hypoglycaemia (4.90 (2.79-8.61)), jaundice (2.58 (1.61-4.13)) and shoulder dystocia (2.72 (1.09-6.78)), but not congenital malformations or perinatal death. Women with T2D had a higher risk of induction (4.03 (2.71-5.99)), caesarean section (2.10 (1.44-3.04)), preterm birth (2.74 (1.78-4.24)) and pre-eclampsia (2.75 (1.49-5.10)). An HbA1c ≥ 6.0% (42 mmol/mol) was associated with increased preterm birth, special care nursery admission, hypoglycaemia and jaundice. Conclusions: Despite availability of preconception care, good glycaemic control and specialist management, T2D remains associated with increased adverse obstetric and neonatal outcomes. Further research to examine predictors of adverse outcomes may assist in targeted antenatal surveillance and management.