Fetal breathing movements

Crystal
I had the Fetal Anatomy Scan a few days ago and I noticed on the paper that the Fetal Breathing column was checked "no". I'm 20 weeks, and the heart rate was 149 but I'm confused what that means?! I have the complete posterior placenta previa but I wouldn't think that has anything to do with it?! I'm not having another ultrasound for another 8 weeks which makes me nervous. Has this happened to anyone else?! It makes me think maybe the babies lungs aren't functioning properly but then again the doctor acted like I was crazy for even being concerned! Any thoughts would help! Thanks ladies!