The goal of this clinical trial is to evaluate the effectiveness of training pregnant women on the decision of having an oral glucose challenge test (GCT), which is recommended by a physician for screening of gestational diabetes mellitus (GDM). Primary hypothesis is that structured training is effective in increasing pregnant women's acceptance of gestational diabetes mellitus (GDM) screening. The effect of training on patients' decision-making regarding gestational diabetes mellitus (GDM) screening was planned to be evaluated. Participants in the control group received standard counseling about GDM screening. Participants in the intervention group received a structured, specific audiovisual educational program supported by a guidebook, lasting approximately 15-20 minutes.