I’m high risk

I’m 17 ive been pregnant before. It turn out to be a blighted ovum. And when I was in the hospital I was told I have one ovary. And I’ve read that if you have one ovary you are high risk of Down syndrome but I do have another ultrasound done this week to see if I have both of my ovaries cause it was hard to look at my pregnancy from being bloated. Is anybody pregnant with one ovary and have a healthy baby? No im not trying to get pregnant but I’m thinking about getting out on the bar to prevent pregnancy