EP29.11: Single umbilical artery: pregnancy management

Abstract

Objectives: Single umbilical artery (SUA), the most common malformation in humans, 1% incidence in singletons, may be an isolated finding in normal fetuses (75%) or associated with chromosomal (5%) and/or other congenital anomalies (20%). The cause is either primary agenesis or secondary thrombotic atrophy of one umbilical artery. The aim of the study was to establish the management of pregnancies with SUA and to evaluate their obstetric outcome. Methods:We performed a retrospective study on a series of singletons detected with SUA. The study group consisted of all pregnancies followed-up 2011-2021 by a single obstetrician. Multiple pregnancies and those obtained after human reproductive technologies were excluded. The detection of the SUA was done at the first trimester screening ultrasound in a transverse view of the fetal pelvis searching the intra-abdominal segment of the umbilical arteries running alongside and around the fetal bladder using colour Doppler.After the detection of SUA, the fetus was carefully monitored for structural anomalies and serial fetal growth scans were performed. Postnatally all cases were followed-up until de age of 1. Results: The incidence of SUA was 0.66%. All cases of SUA were diagnosed in the first trimester and confirmed postnatally. Most were isolated SUA and did not develop IUGR, or complicate with pre-eclampsia or preterm birth. One case of Trisomy 18 was confirmed after karyotyping indicated for detection of other congenital malformations beside SUA and induced abortion was performed at 21w, the other cases of SUA delivered at term, Apgar scores > 8. None congenital malformation was detected postnatally. Conclusions: Most likely the good pregnancy outcome in the study group can be explained by the fact that the cause of SUA was due to primary agenesis of one umbilical artery and not due to thrombotic atrophy. The management and ultrasound follow up of pregnancies detected with SUA should adapt depending on the physiopathological cause of this condition. EP29.12 Prenatal findings and follow up of a child with Trisomy 21 and congenital chylothorax