Girls, I don't even know how to say it (when I was at the first screen…

Girls, I don't even know how to say it (when I was at the first screening, they saw something near the cheeks of the fetus that I didn't understand, they said when you take your tests, your doctor will explain in this situation, my results came in the conclusion: written Low risk for chromosomal abnormalities, what does it mean? The doctor didn't have anything to explain, just said to send the genetic analysis and I read bad thoughts in my head, what if the baby is born with a birth defect ??