“Edwards syndrome, also known as trisomy 18, is a very severe genetic condition that affects how your child’s body develops and grows. Children diagnosed with trisomy 18 have a low birth weight, multiple birth defects and defining physical characteristics.
Edwards syndrome (trisomy 18) can affect anyone. The condition occurs when a person has an extra copy of chromosome 18, which is random and unpredictable. The likelihood that a parent will have a child with Edwards syndrome (trisomy 18) increases with maternal age at the time of pregnancy. If a parent had a child with Edwards syndrome (trisomy 18) and becomes pregnant again, it’s unlikely they’ll have another child diagnosed with the same condition (no more than 1%).”
Cleveland Clinic (https://my.clevelandclinic.org/health/diseases/22172-edwards-syndrome)