Background Metformin has been shown to be safe, effective and acceptable to women with gestational diabetes (GDM), and is recommended as the first-line pharmacological treatment for women who meet the usual criteria for insulin.

Methods We retrospectively reviewed case notes of women with GDM in the Royal Infirmary of Edinburgh (RIE) from January 2009–March 2011. Audit standards derived from local guidelines included: metformin as the first-line glucose-lowering medication in at least 90% of cases; average blood glucose readings <8.0 mmol/L over two weeks in at least 90% of cases (≥8.0 mmol/L was considered ‘poor’ glycaemic control); and postnatal glucose-tolerance-test (GTT) in all cases. Neonatal outcomes were observed.

Results Of the 113 pregnancies reviewed, 82.3% (93/113) of women required glucose-lowering medication. Metformin was used first-line in 94.6% of women requiring medication (88/93), and 99.6% of these continued treatment until delivery. Supplemental insulin was required in 44.3% of cases (39/88). Average blood glucose readings of <8.0 mmol/L were achieved in 93.6%, and 91.2% of cases during the second and third trimesters respectively. 70.8% of women (80/113) attended for postnatal GTT, and 25% of these (20/80) were abnormal. Macrosomia (defined as birth-weight ≥4000 g) affected 20.3% of babies. One baby required admission to the neonatal unit due to hypoglycaemia.

Conclusion In RIE, women with GDM receive appropriate medication. The quality of glycaemic control has been maintained since metformin became the first-line medication. Suboptimal attendance for postnatal GTT must be addressed to optimise the health of these women who are at risk of developing Type 2 diabetes.