Maternal Body Habitus

So I was reading through the results of my 20 week scan this morning and noticed that they're saying I need a second ultrasound to see my baby's spine due to fetal position and maternal body habitus. I googled the term and basically what I'm seeing is they're blaming my weight for the fact that they couldn't get a clear picture of my baby's spine. I'm SLIGHTLY overweight. Are they seriously saying that because I have about 10-15 extra pounds prepregnancy that they can't get a good picture? I feel like this is really offensive to new moms, especially first time moms like me. If there's another reason they would put this down, I'd love to know. But from the looks of it, it looks like they're blaming my weight. Anyone else notice this on their 20 week scan results?