Introduction: Gestational diabetes mellitus (GDM) is the most common metabolic disorder in pregnancy, and is defined as glucose intolerance detected during pregnancy, most commonly in the second and third trimesters. If the disease is not well controlled, various adverse pregnancy outcomes such as arterial hypertension, preeclampsia, polyhydroamnion, oligohydroamnion, cesarean delivery and premature birth are possible. Study structure: cross-sectional study with historical data Objective: To examine the association of maternal outcomes with therapy, time of OGTT, previous history of GDM, and weight gain during pregnancy Methods and subjects: Women treated at Clinical Hospital Center Osijek under the diagnosis of GDM, in the period from 2016. to 2020. The sample size is 400 respondents. Data were collected from patients medical histories. The results are shown in tables, absolute and relative frequencies, and the significance of the differences by the chi-square test with a 95 % confidence interval. Statistical significance will be accepted with p < 0.05. Results: There were no statistically significant differences between the observed outcomes of pregnancy and therapy, the time of OGTT and previous GDM. Mothers who gained more than 15 kg during pregnancy had significantly more arterial hypertension compared to mothers who gained less than 15 kg (P < 0.001). Conclusion: In this study, GDM therapy did not significantly affect maternal pregnancy outcomes, nor did the time of OGTT performed or the presence of a history of previous GDM. The occurrence of arterial hypertension was more common in patients with a total weight gain greater than 15. Arterial hypertension, preeclampsia, and cesarean delivery were more common in mothers with high BMI.