I can vouch for sonographers (and doctors) not always being too careful with their choice of words...
We had "How far along are you?" as one sonographer started, when it was a scan related to fertility problems.
We had "So, twins eh?" just before a scan started, on more than one occasion, when one of the twins was deceased. Same from midwives, doctors and, I kid you not, even the flippin' registrar at the town hall (mention was made of twins on the paperwork from the hospital).
Several references to "she" when he was known and documented to be a boy. One consultant even said she about 2 minutes after calling him she and being corrected that he was indeed a he.
Those were before he was born. After birth, in intensive care he was referred to as she a couple of times, despite them using blue labels on boys' incubators and pink ones on the girls'.
I once went in to hospital to find him with a pink wooly hat on. I swapped it forthwith.
On the other hand, none of any of that seemed to matter much in the great scheme of things. But I certainly wouldn't think you should not read too much in to a slip of the tongue (or indeed their ability to read notes).