EP475: Long-term follow-up on fetuses diagnosed in second trimester with isolated single umbilical artery and normal chromosomal microarray

Abstract

Fetuses diagnosed with isolated Fetal Single Umbilical Artery (iSUA), defined when no additional anatomical abnormalities are detected, and are not associated with significantly increased risk for chromosomal anomalies. However, information on their long-term outcome is lacking. The objective of the current study is to examine the long-term outcomes of fetuses diagnosed in second trimester with iSUA and normal chromosomal microarray assay (CMA). A retrospective review was conducted including all cases referred to our center with iSUA and a normal CMA between 2016 to 2020 (study group). Obstetrical and postnatal medical files were reviewed. Parents were contacted for a structured interview including neurodevelopment development assessment using Ages & Stages Questionary-3 (ASQ-3). A total of 282 cases of iSUA were referred for prenatal counseling, 48 (17%) opted to perform an invasive diagnostic test. The final study group consisted of 45 patients. Pregnancy follow-up was conducted in a dedicated clinic and included prenatal echocardiography and a 3rd-trimester malformation scan. Post-natal follow-up range was 3±2.2 years. In 9 (20%) cases of the study group additional findings were detected downstream: 4 (45%) cases prenatally (esophageal atresia, congenital anomaly of kidney, Severe Intrauterine growth retardation, and VACTERL association). Five cases (55%) showed abnormal findings only postnatally: 3 cases (6.6%) with malformations (brachial cyst and polydactyly and GLI1 pathogenic variant, sacral malformation and heterotopia due to FLNA pathogenic variant, and one case with coloboma - in assessment). 2 cases (4.4%) with functional abnormalities (one with recurrent meningitis and strabismus and one with prematurity and diplegic cerebral palsy) all being under evaluation. Two (4%) additional cases were diagnosed with neurodevelopment delay. ASQ-3 scores in all other study group participants were in the normal range. Fetuses diagnosed with iSUA and normal CMA in the second trimester are at increased risk for anatomical and functional complications including single-gene disorders. Additional findings might be disclosed in later stages of pregnancy but more importantly – can evolve postnatally only. Therefore, an extra risk should be given to the counselee and exome analysis should be considered. Further studies are required to reinforce this data