I haven't had a birth in the hospital since the last patch, but after reading this thread, one thing I noticed is no one has commented on the simsinfo mod. If you have that mod, there is a healthcare section in it, that in addition to giving you info about your sim, it you give a list of all the medical professionals in your game in the GTW Medical career.
When I have had no doctors show up and checked it via the mod, what I found, particularly when you haven't put a sim in the that career, changed the ones you had in the career to another, or the ones you had died, there are none and the game takes quite a while to generate a new NPC doctor, etc. and that is what is causing the delay. Or at least some of the time anyway.
In my game, I do have a bunch of sims in the medical career now and almost always get at least one, and sometimes two, of them showing up to deliver the baby. Usually when my sims spawn in front of the front door, the doctor and nurse spawn there at the same time too. Sometimes one will leave immediately but soon gets replaced by another. I may or may not get a receptionist. If I do, that NPC seems to always spawn at the desk. Otherwise, one never shows up. When none of the playable medical career sims spawn when my sim does, there is a noticeable delay before any medical career sims show up and it's almost always a new NPC, not a playable in the Medical career. In any case, most of the time the spawned NPCs just stand around doing idle animation until the birth clock starts. Then they spring into action and one of them goes to the surgery machine and the birth happens.
One thing that happens that drives me nuts at times though is while waiting for the birth to happen, my active sims continually try to go to the vending machines despite the fact that they have full motives. I have to constantly cancel that action. That has been happening well before the recent thirst/get a drink of water thing that is happening now too so the same thing is not causing it I'm sure. So I usually send them to a computer to play a game until the birth clock starts and that shuts it down.
I have never had a birth fail where I had to try over or give birth at home. They always deliver eventually. Some take a lot longer to do it than others though.
Now, one thing I have learned reading this thread is about checking in. I didn't even know you could even do that during a birth cycle so I've never even tried. So I don't think you have to since I've had so many successful births without doing it. I rarely give birth at home (usually because I waited too long so the sim could finish something they were doing) and the vast majority happen at the hospital.
