Objective:

To address the possible risk factors, eventual pregnancy outcomes, and probable troubles in follow-ups of pregnancies complicated by an isolated single umbilical artery and to provide data on Turkish cases in such an aspect that ethnic divergences may have influence.

Material and Methods:

A total of 16568 singleton pregnancies that were delivered between May 2006 and May 2013 were retrospectively screened. Ninety-three fetuses were found to have an isolated single umbilical artery. One-hundred pregnancies that did not show any structural or chromosomal abnormalities were randomly selected from the rest of the cases to establish the control group. IBM SPSS Statistics 20.0 software was utilized for statistical analysis. Non-parametric data were analyzed with Mann-Whitney U test and were presented as means±standard deviations. P values less than 0.05 were statistically significant. For the adjustment of confounding factors, odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by multiple logistic regression analysis.

Results:

The incidence of small for gestational age (SGA) fetuses and hypertensive disorders in pregnancy was found to be significantly higher in cases with an isolated single umbilical artery (p<0.001 and p=0.022, respectively). Maternal smoking was found to be independently associated with the occurrence of an isolated single umbilical artery (OR: 3.556; 95% CI: 1.104-11.45). The risk of preterm birth was not higher in the study group (OR: 0.538; 95% CI: 0.576-2.873). The incidence of cases who underwent cesarean delivery because of non-reassuring fetal heart trace was similar in the study and control groups (p=0.499).

Conclusion:

Attention should be paid to the development of hypertensive disorders in cases with a diagnosis of an isolated single umbilical artery, and parents should be counseled properly, including the information on increased risk of SGA. Strict follow-up of pregnancies complicated with an isolated single umbilical artery in terms of preterm birth seems unfeasible except in cases with accompanying risk factors for preterm labor.

Keywords: Isolated single umbilical artery, SGA, pregnancy outcome, hypertensive disorders, preterm birth