Background <p>Single umbilical artery (SUA) and umbilical artery thrombosis (UAT) are associated with adverse fetal outcomes, yet comparative data on their risk factors and clinical implications are limited. This study aims to evaluate the risk factors and their impact on pregnancy outcomes associated with SUA and UAT, and to assess the applicability of SUA management strategies to UAT.</p> Methods <p>This retrospective cohort study investigated pregnancies diagnosed with SUA and UAT at a tertiary hospital from 2017 to 2021. Medical history, birth details, and diagnoses were collected from medical records. Potential causes of SUA and UAT were explored by comparative analyses with a control group and further regression analyses. Logistic regression models evaluated the possible adverse pregnancy outcomes of SUA and UAT, and a comparative analysis of adverse outcomes associated with these two conditions was performed.</p> Results <p>Previous cesarean delivery, abnormal umbilical cord insertion and in vitro fertilization (IVF) were identified as independent risk factors for SUA, whereas nulliparity, previous cesarean delivery, abnormal umbilical cord insertion and IVF were identified as independent risk factors for UAT. SUA was associated with low birth weight (LBW), preterm labor, neonatal respiratory distress syndrome (NRDS), congenital heart defects (CHD), and urinary system malformations (USM). UAT was associated with LBW, fetal growth restriction (FGR), preterm labor, fetal distress, NRDS, and CHD. Fetuses with UAT had significantly lower birth weight and higher rates of LBW, FGR, preterm labor, and fetal distress compared with SUA.</p> Conclusions <p>UAT encompasses the risk factors and adverse pregnancy outcomes associated with SUA, suggesting that similar prenatal and postnatal care strategies may be applicable. However, due to the higher risk profile and severity of outcomes in UAT, future research should focus on developing more specialized care options to address these challenges.</p>