
One of my bitches had a c section for her third and last litter in 2001 when she was just over 6 1/2 years old, there were only 4 pups, and she had been in first stage for 48 hours, and was overdue, but not getting anywhere (inertia). Her first litter was Oct 97 and second Nov 98 and she delivered 8 and 7 pups respecitvely no problem, though she was restless and panting (first stage) for a full 24 hours!
I whelped a bitch for friends in the breed, and she had unfortunately a bout of enteritis half way through pregnancey (before coming to me) and was very off her food, and I had to force feed her. She had secondary Inertia, as she was run down, but did well after they were born, but needed Calcium, as had no reserves!
In these cases I think it was jus5 unfortunate circumstances. but where there is a family pattern of C sections for the same reason it could be familial!