High proportion of overt diabetes mellitus in pregnancy and missed opportunity for early detection of diabetes at a tertiary care centre in Pakistan

OBJECTIVES: To determine the frequency of diabetes in pregnancy (DIP), namely pre-gestational, gestational (GDM) and overt diabetes mellitus (DM) in women registered for delivery. METHODS: A retrospective chart review of antenatal women registered between January 01 to August 31, 2017 was performed. Gestational age, diagnosis of DIP, glucose levels at diagnosis and other relevant data was extracted. The effect of various fasting blood glucose (FBG) thresholds for diagnosis of DIP was assessed. RESULTS: DIP was diagnosed in 21.8% women (pre-gestational: 2%, GDM: 81.2%, overt: DM: 16.8%). In early registrants, 30.2% were detected through screening. However, 55.3% of women registered late. Women with pre-gestational DM were older, had more miscarriages, and greater personal and family history of diabetes versus GDM and overt DM. Raising the diagnostic threshold of FBG from 92 mg/dl to 95 mg/dl missed three women (0.1%) and to 105 mg/dl, missed six women (0.2%). CONCLUSION: We observed a high proportion of overt DM. In early registrants, almost one third of DIP was diagnosed in the first half of pregnancy, an opportunity missed in late registrants. Altering diagnostic thresholds of DIP affected only a small proportion of women.