This study aimed to evaluate whether the presence of an isolated single umbilical artery (iSUA) is associated with a dverseperinatal outcomes.Fifty-one patients with iSUA and 54 controls were enrolled in the case-control study. Demographic characteristics andperinatal outcomes were recorded.All patients had normal umbilical artery (UMA) Doppler findings, and their de tailed ultrasound weeks were between 18 and23 weeks. The birth weights of the babies in the iSUA group were significantly lower than the control group(2898.82±434.56 g vs 3143.70±419.09 g, p=0.004). In the iSUA group, oligohydramnios (7.8% vs 0%) , preterm prematurerupture of membranes (PPROM) (3.9% vs 0%), preterm delivery (9.8% vs 3.7%), small for gestational age (SGA) (11.8% vs3.7%) and neonatal intensive care unit (NICU) (2% vs 0%) admission rates were higher than control group, but there wasno statistical significance (p>0.05). But the total adverse pregnancy outcomes were observed in 35.3% (18/51) of caseswith iSUA is higher than controls 7.4% (4/54) (p=0.001).In our study, iSUA is found to be associated with low newborn weight. In the iSUA group, oligohydramnios, PPROM,preterm delivery, SGA, and NICU admission rates were high, but there was no statistical significance. But the total adversepregnancy outcomes were higher in the iSUA group. These results indicate that close follow-up is essential to prevent andmanage adverse perinatal outcomes in iSUA patients.