Which of the following is a common cause of amenorrhea in women of reproductive age?

Hypothyroidism is a common cause of amenorrhea in women of reproductive age due to its significant impact on hormone production and regulation. The thyroid gland plays a crucial role in the overall hormonal balance in the body, including the hormones that regulate the menstrual cycle. An underactive thyroid leads to decreased levels of thyroxine (T4) and triiodothyronine (T3), which can result in elevated thyroid-stimulating hormone (TSH) levels. This imbalance can disrupt the hypothalamic-pituitary-ovarian axis, leading to irregularities in the menstrual cycle or complete cessation of menstruation (amenorrhea).

In comparison, while diabetes mellitus can cause various hormonal changes and may indirectly affect menstruation, it is not as direct a cause of amenorrhea as hypothyroidism. Anemia, particularly if not severe, typically does not lead to amenorrhea but rather may cause alterations in menstrual blood flow. Kidney disease can lead to hormonal changes as well but is less commonly associated with amenorrhea compared to hypothyroidism, which specifically interferes with the hormonal pathways involved in the menstrual cycle.