A nurse is reviewing the medical record of a client who is requesting combination oral contraceptives. Which of the following conditions in the client's history is a contraindication to the use of combination oral contraceptives?

A. Hyperthyroidism: Although thyroid function should be monitored, hyperthyroidism itself is not a contraindication for combination oral contraceptives. However, uncontrolled hyperthyroidism may require careful evaluation before starting any hormonal therapy. B. Hypocalcemia: Low calcium levels do not directly affect the safety of combination oral contraceptives, so this condition is not a contraindication. Oral contraceptives do not typically influence calcium metabolism in a way that would cause harm in hypocalcemic patients. C. Thrombophlebitis: This condition indicates a history of blood clots or venous inflammation, which significantly increases the risk of thromboembolism with combination oral contraceptives due to their estrogen content. Therefore, thrombophlebitis is a contraindication. D. Diverticulosis: This condition affects the colon and is not related to the risks associated with combination oral contraceptives. It does not contraindicate their use.