Prenatally Diagnosed Single Umbilical Artery (SUA) - Retrospective Analysis of 1169 Fetuses

The incidence of a fetal single umbilical artery (SUA) is about 0.5 % and has been associated with an increased risk of congenital malformations, fetal aneuploidy and intrauterine growth restriction (IUGR).

A retrospective analysis of 1169 women with singleton pregnancies diagnosed with fetal SUA between 1997 and 2014 in a specialized practice for prenatal diagnostics has been performed. Data was obtained on maternal and fetal findings as well as pregnancy outcome.

989 (84.6 %) fetuses showed an isolated SUA (iSUA) while 180 (15.4 %) presented with SUA and additional structural and/or chromosomal abnormalities. Structural malformations were distributed as follows: 9.0 % cardiovascular, 3.5 % urogenital, 2.9 % musculoskeletal, 3.0 % gastrointestinal and 2.1 % cerebral. 2.1 % of the fetuses had chromosomal aberrations. 50.8 % (49.2 %) of the fetuses were female (male) and right vs. left SUA was found in 64.2 % (35.8 %) of the cases. Fetuses with SUA and additional abnormalities showed lower rates of live births (85.0 % vs. 98.5 %, p < 0.001), a lower median birth weight (2825 g vs. 3220 g, p < 0.001), higher rates of preterm delivery before week 34 + 0 (13.7 % vs. 3.8 %, p < 0.001) and weighed less than the 5th growth percentile in 21.6 % vs. 9.3 % (p < 0.001) of the fetuses with iSUA. In 5.1 % (60) of the children, chromosomal or structural abnormalities were detected post-partum.

Once fetal SUA is diagnosed, intense sonoanatomy of the fetus is required and, if associated malformations are found, genetic testing must be offered. In iSUA intermittent biometry is recommended for the early detection of IUGR but additional genetic testing is not necessarily recommended.