Single Umbilical Artery

Meron po ba dito nagkaroon rin ng Single Umbilical Artery case? Nakita po kasi sa ultrasound na instead of 2 arteries yung nasa umbilical cord ni baby, 1 artery lang po yung nakita.. A bit worried lang po.. on Week 27 Day 2 of pregnancy na po.. Thank you in advance & God bless po sa mga makakasagot..