1:70 chance of Trisomy 18

My husband and I are expecting a baby boy in May!' We recently got a quad screening and our results showed that we are at a n increased risk for trisomy 18 with a 1 in 7 0 odd. We are worried. We will be returning to our doctor to get a 2nd ultrasound done to check for trisomy 18 markers. Do we have a good chance of having a healthy baby boy? We are so worried thank you all for your time