20 week scan question

So the tech wasn’t able to get all of the pictures of the heart they needed. Doctor said we’d have to come back next month to get those pictures.

we’re scheduled to come back end of next month to get the rest of them.

Does that mean they may have seen something they’re just unsure since they didn’t get all the pics & want to see the rest of the heart for that reason?

Or do they seriously HAVE to get every picture of the heart & that’s why we have to come back?

Sorry if this is a stupid question, I’m just nervous!