I lost one ovary to a v.large borderline malignant tumour in 2001 (I have since, rather miraculously and despite a knackered tube, had 2 children). I am pretty sure I had to sign something saying that there was a possibility I would lose both ovaries/tubes, so as to cover all eventualities. But they do try VERY HARD to keep as much intact as possible, they can also remove only part of an ovary, it doesn't have to be the whole lot.
The consultant did tell me that should I need a hysterectomy they wouldn't do it there and then, but in another operation with further consent. Which was a great comfort to someone of 27 who wanted children
I would ring the hospital to confirm it all. It's very easy NOT to ask enough questions - I know I made that mistake - and I do find that they tend to forget just how awful anything to do with your fertility is, and they are used to dealing with (and no offence meant here) so many people, and ones with worse problems, so you can get the brush off all too easily. I remember being reduced to hysterics by one doctor who told me to stop making such a fuss (I'd simply asked for some straight answers re what had actually been done) when the lady next to me had had to have a hysterectomy. I'd just had major gynaecological surgery, much more extensive than what I was expecting
I only found out a lot of specifics to do with my tumour a year or so later by pinning down a more helpful doctor.
It's horrible, I know, please try to get hold of someone and check what they're actually confirming. Don't worry about making a nuisance of yourself (like I did), get some answers, it's IMPORTANT.
Sorry to go on but this is very close to the bone for me (can you tell?)