The parents of a child with sickle cell anemia ask why their child did not have a sickle cell crisis until he was approximately 6 months old. How should the nurse respond?
Correct Answer: C
Rationale: The correct answer is C. Fetal hemoglobin (HbF) is present in high levels during early infancy, inhibiting sickling unlike adult hemoglobin (HbS). As the levels of HbF decrease and HbS increases, the risk of sickling and crises becomes more pronounced, typically after 6 months of age. Choice A is incorrect because it assumes the crisis went unnoticed, which is not supported by medical knowledge. Choice B is incorrect as it questions the child's diagnosis rather than explaining the phenomenon of delayed crises. Choice D is incorrect as it does not provide the parents with the necessary information regarding their query.