The nurse is caring for a client currently taking a combination birth control pill for contraception prevention. Which adverse effect would the nurse closely monitor for associated with this medication?

A. While hormonal contraceptives can affect blood pressure, the risk of significant hypertension is less immediate than thromboembolism. B. Dysfunctional uterine bleeding can occur but is generally not as serious as thromboembolism and may resolve with continued use. C. Combination birth control pills increase the risk of thromboembolic events, such as deep vein thrombosis (DVT) and pulmonary embolism, making it essential to monitor for signs of these complications. D. Osteoporosis is a long-term concern but is not an acute effect of combination birth control pills; monitoring for thromboembolism is more critical.