A nurse is teaching a client about potential adverse effects of oral contraceptives. For which of the following adverse effects should the nurse instruct the client to notify the provider immediately?

Choice A rationale Nausea is a very common, generally mild, and often transient side effect of oral contraceptives, usually caused by the estrogen component. It typically improves over a few cycles as the body adjusts to the hormonal changes and does not usually necessitate immediate notification of the healthcare provider. Choice B rationale Abdominal bloating is a frequent and minor adverse effect of hormonal contraception, often related to fluid retention or altered gastrointestinal motility due to hormonal fluctuation, which is usually self-limiting or manageable with minor adjustments, thus not requiring urgent reporting. Choice C rationale Breast tenderness or mastalgia is a common, dose-related side effect linked to hormonal stimulation (estrogen and/or progestin) of the mammary tissue, similar to premenstrual symptoms, and is generally considered a nuisance rather than an immediate danger sign. Choice D rationale Persistent headaches, especially if severe, unilateral, or associated with visual changes, can be a symptom of a serious adverse event like a cerebrovascular accident (stroke) or thrombotic events (e.g., cerebral venous thrombosis), which are rare but serious risks associated with hormonal contraceptives, necessitating immediate medical evaluation.