Background Mothers with lower birth weight (LBW) offspring have been found to be associated with cardiovascular disease (CVD) morbidity, which shares many risk factors with diabetes.

Aims To investigate the relation between offspring birth weight and maternal risk of mortality from diabetes.

Methods A total of 1 400 383 singletons of primigravida registered in Taiwan between 1978 and 1987 were followed to the end of 2006. The offspring birth weight was assessed with and without standardisation for the gestational age of offspring. Cox model was used to estimate the HR of maternal diabetes mortality in relation to offspring birth weights.

Results Altogether, 812 (5.8%) mothers died of diabetes. Mothers with LBW (<2500 g) and macrosomia (>4000 g) offspring were both at increased risks of mortality from diabetes with HR 1.76 (95% CI 1.46 to 2.19) and 2.86 (95% CI 2.32 to 3.53), respectively. Similar results were seen while birth weight was standardised for gestational age.

Conclusions This cohort study found that mothers with LBW and macrosomia offspring had an increased mortality risk of diabetes. This relationship could be attributable to the possible pathway of intergenerational effects or maternal insulin resistance due to maladaptation to pregnancy.