Perinatal results following the prenatal ultrasound diagnosis of single umbilical artery

OBJECTIVE. To study the perinatal results in our population, following the prenatal ultrasound diagnosis of a single umbilical artery (SUA), as this alteration is associated with fetal malformations, chromosomal abnormality, and poor perinatal results. MATERIALS AND METHODS. A retrospective review of all obstetric ultrasounds carried out between October 2000 and December 2003 in our service, obtaining the postnatal results of the fetuses diagnosed with an SUA. RESULTS. From a total of 5,987 pregnant patients examined by ultrasound scan at 20th week, an SUA was found in 40 cases, representing an incidence of 0.7%. Of these, 84.6% were normal pregnancies at birth and 15.4% presented other malformations and/or chromosomal abnormalities. No aneuploidy was found in pregnancies where there were no other associated findings in the ultrasound scan at 20 weeks. All cases with serious congenital malformations accompanying the SUA were diagnosed prenatally. There was a 5% of perinatal mortality rate among our fetuses with SUA, which represents a mortality rate 10 times greater than the overall rate among our patients. CONCLUSIONS. The ultrasound discovery of an SUA implies the meticulous search for other associated malformations, and in the absence of these, the risk of a chromosomal abnormality is very low, unless it is a high-risk patient. However, the growth and wellbeing of the fetus must be carefully monitored in the last 3 months, although the ultrasound scan does not show any other associated alterations.