The inclusion criteria were a pregnancy duration of 22 weeks or more and a birth weight of 500 g or more. The absence of reliable data in the clinical history was a criterion for exclusion.During the 6-year study period, 269 565 pregnancies were recorded,8626 (3.2%) of which were twin pregnancies. Pregestational DM was present in 68 mothers. Therefore, the two complications coexisted in 2.5 of 10 000 pregnancies, and the mother had pregestational DM in 7.9 of 1000 twin pregnancies.