<p class="ql-align-justify"><strong style="color: rgb(33, 33, 33);">Objective:</strong><span style="color: rgb(33, 33, 33);"> To reveal the factors that may influence the success of prostaglandin E2 treatment applied for cervical ripening when induction of labor was indicated.</span> <p class="ql-align-justify"><strong style="color: rgb(33, 33, 33);">Materials and methods: </strong><span style="color: rgb(33, 33, 33);">Pregnant women with fetal cardiac activity, Bishop score of under 3, cephalic presentation, reactive nonstress test (NST) and without any active contractions were included. </span>Controlled release ovules containing 10 mg dinoprostone <span style="color: rgb(33, 33, 33);">were used for cervical ripening. Bishop score of greater than 5 was defined as successful treatment group and lesser than 5 was identified as the group of failed treatment. Age, gravida, parity, vaginal pH, time to the first contraction and time to the active contractions, fetal weight, fetal abdominal circumference (AC) and biparietal diameter (BPD) were compared between the two groups and </span><span style="color: rgb(34, 34, 34);">assessed whether these factors influence the success of the dinoprostone treatment.</span> <p class="ql-align-justify"><strong>Results: </strong>While maternal age, parity, gestational day calculated on the basis of last menstrual period, fetal BPD, AC measurements were not significant in determining the success (p:0,54; p:0.06; p:0.11; p:0.123; p:0.127); gravida,<span style="color: rgb(33, 33, 33);"> cervical dilation and effacement, vaginal pH, time to the first contraction and time to the active contractions, fetal weight were significant in determining the success </span>of treatment (p:0.017; p:0.021; p:0.007; p<0.01; p<0.01; p<0.01; p:0.046) <p class="ql-align-justify"><strong>Conclusion: </strong><span style="color: rgb(33, 33, 33);">Prior to treatment </span>with controlled release ovules containing 10 mg dinoprostone, o<span style="color: rgb(33, 33, 33);">bstetric history, physical and ultrasonographic examination of patients may predict treatment responses. Patients with higher number of pregnancies, greater cervical dilation, effacement, higher vaginal pH and early appearance of first and effective contractions may increase treatment success.</span>