From a practical stance, the children are at nursery around about the same time that most working mothers/fathers have, so this aspect is not unusual or related to being a doctor, so it's an issue of you potentially giving up all the training to be a SAHM.
My step mum was a doctor, in the USA, so the training was a bit different, and she specialised as a pathologist and retrained as a GP, which seemed to work out better.
However, I know lots of doctors. A close friend of mine works as a locum on the weekends, another retrained as a music teacher as she hated being a doctor. Another is a consultant, who irritatingly is at all the school functions and able to juggle. She is a specialist and mostly does clinics and some rotations, and relied on nannies when her children were younger, with her husband who also has an on call commitment.
However, as many others have pointed out, the maternal guilt will be there more or less whatever profession.
Lastly, my step mum was a doctor and from the child's viewpoint, there were some things that I missed, and maybe had fantasies that she would be the mum who would bake cookies or whatever, but she wasn't that person. She burned food, she was terrible at most things domestic, but she was a loving, supportive mum.