My 3 year old is afraid I'm going to die in childbirth :(

Has anyone had one of their children express fear of mommy dying in childbirth? My three year old asked how the baby will come out. I've had three c-sections so this delivery will be one as well. I explained that the dr will do surgery and the baby will be born. My son then said sadly "and then mommy will die." It breaks my heart that he fears this and I don't know how to ease his fears.