Nokea
A professional athlete in her mid-20s has not had a menstrual cycle for 5 years, although a bone density scan revealed normal skeletal mineralization. Which of the following facts elicited during the taking of her medical history may explain these observations?
Correct Answer: D
Rationale: The correct answer is D: Her plasma estrogen concentration is very low. The absence of menstrual cycles in a young athlete with normal bone density suggests hypothalamic dysfunction affecting the menstrual cycle. This can result from low estrogen levels, which are essential for the regulation of menstrual cycles. Low estrogen levels can be caused by intense physical activity, leading to suppression of the hypothalamic-pituitary-ovarian axis.
Choice A is incorrect because a high-carbohydrate diet alone is unlikely to cause amenorrhea. Choice B is irrelevant to the absence of menstrual cycles and normal bone density in the athlete. Choice C, elevated blood pressure, is also unrelated to the situation described.