Single umbilical artery (SUA) is considered an ultrasound marker of anomalies. Although it may be present in about 5% of normal gestations, it has been observed to be associated with an increased risk of intrauterine growth retardation, cardiac, genitourinary and gastrointestinal malformations, as well as with the appearance of chromosomal anomalies such as trisomy 21 and 18. Objectives: This study aims to check whether the presence of isolated SUA (ISUA) is related to adverse perinatal outcomes. Methods: This is a descriptive, observational and retrospective study with a total of 1266 gestations were studied (1189 normal gestations and deliveries collected from the registry of the Hospital Univeritario de Salamanca, during the period from January 1st to August 31st, 2023 and 77 cases of ISUA). Results: The presence of ISUA was associated with a lower gestational age (38 vs 39 weeks) and a lower birth weight (3013 vs 3181 g) though not increasing the prematurity rate. No significant differences were found in the increase in malformations, genetic disorders, Apgar test, pH at birth or admissions in the neonatal ICU. Conclusions: The presence of ISUA during gestation is associated with lower gestational age and lower birth weight though this did not result in a higher rate of prematurity or an increase in the number of admissions associated with low birth weight. No significant association was found between the presence of ISUA and genetic disorders or fetal malformations. Neither were worse Apgar test scores or lower pH values found in these newborns.