Objective Maternal diabetes substantially increases the risk of late IUD. A greater understanding of the underlying mechanism might allow identification of pregnancies at increased risk. We have studied post-mortem reports to investigate differences between IUD of fetuses from women with and without diabetes.

Methods From the Centre for Maternal and Child Enquiries (CMACE), we obtained post mortem reports of cases of perinatal death in women with and without diabetes. Case pairs were matched for gestational age, birth weight, maternal BMI, deprivation index and ethnicity. We excluded cases/controls with multiple birth, lethal congenital abnormality, and neonatal death.

Results Data are presented on 24 pairs; gestational ages ranged from 173 to 280 days and birth weights from 150 to 4650g. In women with diabetes, the mean placental weight was significantly less than in controls (328g vs 399g; p=0.034; 95% confidence interval -135 to -6g) and the gestational age corrected placental weight was 0.81 (SEM 0.41) standard deviations below population reference values (P=0.05). Brain and spleen weights were significantly lower in the infants of diabetic mothers (brain: mean 235 (SEM 25)g vs 274 (27)g; p=0.032; spleen: 3.5 (0.7)g vs 5.5 (1.1)g; p=0.04). There was a trend for the thymus and liver to be lighter and the heart heavier in the fetuses of diabetic mothers.

Conclusion In pregnancies in women with diabetes which end in late IUD, the placenta, brain and spleen are lighter than in controls and we postulate placental and organ growth may identify diabetic women at risk of IU.