Continuity mistake: In the scene where Thomas J. pulls the fish out of the water, the hook falls out of the fish's mouth twice.
Continuity mistake: Vada loses the right handlebar streamer in the garage, but later in the movie it's the left streamer that is missing. At the very end we see that she has both streamers. (00:35:15 - 01:16:25)
Answer: She still died due to complications from childbirth, despite living another couple of days. Hence why Vada believes that she "killed" her mother. Jane Seymour, the third wife of Henry VIII, also died from complications, but she lived for two weeks after.
To add an additional example to your accurate answer, a condition like postpartum pre-eclampsia (extreme hypertension) can occur from a few days to six weeks after giving birth and is sometimes fatal.
raywest ★