One artery umbilical cord

Am 22 wks with our first baby. We just found out we are having a girl a week ago! Our only concern is that her umbilical cord only has 1 artery instead of two and 1 vein. The dr. Didn't seem too concerned about it, he just said it puts me in an increased risk for abnormalities, but said baby looked healthy and growing accordingly. Has anyone ever heard of this or experienced it?