Yep - front opening nighties etc are the best ....
As @Sister says - take the shawl or wrap with you to hospital to add layers to your warmth as the aircon can get fairly cold too. Also take some light reading matter, some 'treats' (like mints or similar) and also ear plugs & eye masks (like they give you on Airplanes!) Hospitals are incredibly bright & noisy places!
I also found that Short stories (like magazines/Readers Digest/puzzles etc) are better than serious books etc ..... as nursing staff are popping in & out every few hours to annoy you!!
All the best xx