Which assessment is crucial before administering oral combined contraceptive therapy to an adolescent?

Before administering oral combined contraceptive therapy to an adolescent, measuring blood pressure is crucial because hormonal contraceptives can potentially increase the risk of thromboembolic events, particularly in individuals with elevated blood pressure. The use of combined oral contraceptives may exacerbate hypertension, leading to serious health consequences, including stroke or heart attack.

Assessing blood pressure helps ensure that the adolescent falls within a safe range for starting such therapy. If the blood pressure is significantly elevated, healthcare providers may consider alternative contraceptive methods or additional evaluation and management of hypertension before initiating combined hormonal contraceptive therapy.

While family history of breast cancer, pelvic ultrasound, and thyroid function tests can be relevant in certain contexts, they are not as immediately critical as blood pressure assessment when it comes to the safe initiation of oral contraceptives. These other assessments may contribute to a comprehensive view of the patient's health but do not carry the same direct implications for the immediate use of combined contraceptives.