Trends in prevalence and outcomes of pregnancy in women with pre-existing type I and type II diabetes

Objective To describe recent trends in prevalence, outcomes and indicators of care for women with pre-existing type I or type II diabetes. Design Regional population-based survey. Setting All maternity units in the North of England. Population A total of 1258 pregnancies in women with pre-existing diabetes delivered between 1996 and 2004. Methods Data from the Northern Diabetic Pregnancy Survey. Outcome of pregnancy cross-validated with the Northern Congenital Abnormality Survey and the Northern Perinatal Mortality Survey. Main outcome measures Perinatal mortality, congenital anomaly and total adverse perinatal outcome (perinatal mortality and live births with congenital anomaly). Results The prevalence of pregestational diabetes increased from 3.1 per 1000 births in 1996-98 to 4.7 per 1000 in 2002-04 (test for linear trend, P < 0.0001), driven mainly by a sharp increase in type II diabetes. Perinatal mortality declined from 48 per 1000 births in 1996-98 to 23 per 1000 in 2002-04 (P = 0.064). There was a significant reduction in total adverse perinatal outcome rate (P = 0.0194) from 142 per 1000 in 1996-98 to 86 per 1000 in 2002-04. There were substantial improvements in indicators of care before and during pregnancy and in glycaemic control throughout pregnancy, but indicators of preconceptual care, such as use of folic acid, remained disappointing. Conclusion We observed improvements in pregnancy care and outcomes for women with diabetes in a region with an established audit and feedback cycle. There remains considerable scope for further improvement, particularly in periconceptual glycaemic control. The rising prevalence of type II diabetes presents a challenge to further improvement.