Obstetric and perinatal outcomes in pregnancies complicated by Type 1 and Type 2 diabetes:influences of glycaemic control, obesity and social disadvantage

AIMS: To compare obstetric and perinatal outcomes in women with Type 1 and Type 2 diabetes and relate these to maternal risk factors. METHODS: Prospective cohort study of 682 consecutive diabetic pregnancies in East Anglia during 2006-2009. Relationships between congenital malformation, perinatal mortality and perinatal morbidity (large for gestational age, preterm delivery, neonatal care) with maternal age, parity, ethnicity, glycaemic control, obesity and social disadvantage were examined using bivariable and multivariate models. RESULTS: There were 408 (59.8%) Type 1 and 274 (40.2%) Type 2 diabetes pregnancies. Women with Type 2 diabetes were older (P < 0.001), heavier (P < 0.0001), more frequently multiparous (P < 0.001), more ethnically diverse (p < 0.0001) and more socially disadvantaged (P = 0.0004). Although women with Type 2 diabetes had shorter duration of diabetes (P < 0.0001) and better pre-conception glycaemic control [HbA(1c) 52 mmol/mol (6.9%) Type 2 diabetes vs. 63 mmol/l (7.9%) Type 1 diabetes; p < 0.0001), rates of congenital malformation and perinatal mortality were comparable. Women with Type 2 diabetes had fewer large-for-gestational-age infants (37.6 vs. 52.9%, P < 0.0008), fewer preterm deliveries (17.5 vs. 37.1%, P < 0.0001) and their offspring had fewer neonatal care admissions (29.8 vs. 43.2%, P = 0.001). Third trimester HbA(1c) (OR 1.35, 95% CI 1.09-1.67, P = 0.006) and social disadvantage (OR 0.80, 95% CI 0.67-0.98; P = 0.03) were risk factors for large for gestational age. CONCLUSIONS: Despite increased age, parity, obesity and social disadvantage, women with Type 2 diabetes had better glycaemic control, fewer large-for-gestational-age infants, fewer preterm deliveries and fewer neonatal care admissions. Better tools are needed to improve glycaemic control and reduce the rates of large for gestational age, particularly in Type 1 diabetes.