USG is as good as the operator doing it.
Visualised extent means whatever the operator could see, it was normal. If it was done by a radiologist/ obstetrician then don't worry at all, its all normal.
There are some small centres where trained technicians do it, I wouldn't be sure about those reports and would advise you to followup with your obgyn specialist.
Next Steps
Consult your obgyn specialist if you haven't for regular antenatal checkup, USG alone is not sufficient to comment on overall health of the fetus.