Congenital heart disease and adverse perinatal outcome in fetuses with confirmed isolated single functioning umbilical artery.

To examine the association between isolated single umbilical artery (SUA) and congenital heart disease/adverse perinatal outcome in an Australian tertiary centre. The study population was comprised of fetuses diagnosed with SUA at the mid-trimester scan between May 2003 and March 2009 during detailed ultrasound examination at The Royal Women's Hospital Melbourne, Australia. Colour Doppler was used to visualise the umbilical arteries adjacent to the fetal bladder and in a section of a free loop of cord. The diagnosis of SUA was confirmed on histopathology examination of the placenta and umbilical cord. Monochorionic twins, fetuses with chromosomal abnormalities or concurrent extracardiac anomalies were excluded from the study. A total of 261 fetuses with SUA were identified in the study period and 146 (59%) cases were isolated; no chromosomal or extracardiac abnormalities were present. Complete data were available in 104/146 pregnancies (71.2%). The mean gestational age at diagnosis was 21 weeks. A cardiac anomaly was detected in 19 of these fetuses (13.0%): six hypoplastic left heart syndromes; three coarctations of the aorta; two tetralogies of Fallot; two hypoplastic right heart syndromes; two pulmonary atresia/stenosis; one absent ductus venosus with cardiomegaly; one left isomerism; one right isomerism and one transposition of the great arteries. Fetal growth restriction was present in 9.8% (10) and preterm delivery before 34 weeks occurred in nine cases (8.7%). Our study has shown that isolated SUA is associated with cardiac anomalies, but is not associated with increased frequency of FGR and preterm delivery before 34 weeks.