The distribution of variables was assessed using the Kolmogorov Smirnov test. Differences between the groups were analyzed using the t test. For the comparison of qualitative variables, the χ2 test or the Fisher exact test were used (the Fisher exact test was used if a value
was expected to be lower than 5). Logistic regressionwas used to assess the influence of twin pregnancy on perinatal outcomes, with maternal characteristics (age, bodymass index [BMI], and parity) and the severity of diabetes as covariates. Severe diabeteswas defined by the presence of
at least one of the following complications: retinopathy, nephropathy,chronic hypertension, and peripheral neuropathy.