It depends on a lot of factors. If the hospital has 24h anesthesiology, a stat c-section will happen faster than a hospital that has on-call anesthesia. Are all the operating rooms in use or not? Is there an OR prepped now or not? Can the mother be safely put under general or will her airway be compromised? Yes, there are stat c-sections where it has taken 6 minutes or less - usually in larger, better equipped hospitals. Between 20 and 30 minutes is the standard time for decision to incision for a stat c-section. Remember that it takes time to ready the mother even if the OR is prepped ahead of time, so there will always be a further delay if you are transporting than if you are already in the hospital. You will almost never be able to come in the door and have a c-section immediately, even if someone has called ahead because at the very least, you will usually be triaged, there will have to be a diagnosis, and you will have to be prepped. You may have to go upstairs in an elevator. There may be an ultrasound so the surgeon can safely visualize the baby. Everything takes time.
Transporting in late labor - expect everything to take triple the amount of time it normally takes. This is where your midwife's skill and readiness really matters, both in predicting major crises and transporting before something minor becomes major, and because in a crisis pre-hospital care can make all the difference between a happy outcome and a tragic one. It actually might be a good idea, to set your mind at ease, to talk to an OB at the hospital to find out what the procedure is for a home birth transfer on their end, and then with your midwife to find out her procedure. It might be much faster than what I have described or much slower. You should have this information either way.
The absolute risk of these types of "every minute counts" emergencies is very low, but you do take on some additional risk the further away from the hospital you are, because unfortunately if it is that serious, the impact of those few extra minutes can be incredibly high.
I live 2 minutes from my hospital and 7 minutes, with traffic, from the one with the NICU and the better ER. I experienced a precipitous birth at home. I was healthy and low risk and in fact on my way to the hospital to be checked. My water broke and I couldn't walk down the stairs so we called 911, they arrived promptly, but as my daughter was crowning. She had a complication around the time we called 911. They were not able to transport me or my baby until she had finished being born. It took 40 minutes to get to the hospital from the time my water broke/we called 911, and she was transported within moments of birth - they had her in the ER, met by a NICU team, within 8 minutes. It wasn't fast enough. If my water had broken two minutes later, I would have been in my car and at the door of my hospital, and my daughter might be alive today - because she could have had help getting out faster, and she would have had immediate respiratory assistance and a faster transfusion. It is rare, but these kinds of things do happen, and when they happen minutes count. For my daughter's complication the number one predictor of death is where it happens - in or out of the hospital.
Again, I'm not saying this is a reason not to have a home birth. You eliminate a majority of risk just by having good screening and a cautious midwife. But it's real - complications happen, and babies die... sometimes being two minutes away might as well be an hour. And yes they even die in hospitals, because childbirth is dangerous sometimes. There are no guarantees. It's not fear mongering, I promise. You don't want to find out this sort of thing is possible the way I did.
Ultimately, though, the best way to make your decision is based on good information about your midwife and your hospital, your health history, your baby, and your own personal feelings of risk, and your needs in the birth, and not on my speculations or anyone else's about how quick a hospital transfer can be. Hospitals do save lives, but you have to get there in time.
Edited by cyclamen - 11/1/13 at 9:37pm