I have also had a missed miscarriage. I'm so sorry you're going through this.
In my case I turned up for my 12 week scan and our baby's heart had stopped around 9 weeks.
The hospital made me wait a week to confirm development had stopped, then provided me with the option of either medical or surgical.
I didn't want surgical intervention initially, so tried medical. Unfortunately, this didn't work the first time, so I tried again. It didn't work the second time and in the end I ended up being told I had to have surgery as it can be detrimental to carry for too long.
The advice I would give is to give the medical a go once if you want to, but I wouldn't try twice.
Many people just opt for surgery straight away. And, honestly, it wasn't as bad as I thought it would be. Before I knew it I was awake (feeling a bit drunk!) and having a nice cup of tea and toast. :) And I finally felt I could move on after 1.5 months of carrying post fetal death.
Be gentle with yourself and very best wishes.
PS. I have conceived again since and although it ended in a very very early miscarriage once more - with no intervention needed this time - I've absolutely no doubt my body is able to conceive and carry just fine. :) And I've seen so many other women say they've had lovely healthy babies since. Seems to be a strange anomaly and maybe one day we'll know how/why. I know I was desperate to know why, in case it could be prevented in future, so I understand. But we couldn't have done anything and it certainly isn't likely to keep happening. It's very rare. We'll get there. X