Which of the following patient statements about the method of action of emergency contraception (Plan B) indicates a need for further teaching by the nurse?

Choice A rationale

The placenta is a crucial endocrine organ that synthesizes and secretes several hormones vital for maintaining pregnancy. These include human chorionic gonadotropin (hCG), progesterone, estrogen, and human placental lactogen (hPL), also known as human chorionic somatomammotropin (hCS). These hormones collectively support the uterine environment, prevent maternal immune rejection, and promote fetal growth and development throughout gestation.

Choice B rationale

The placenta is indeed responsible for producing key hormones such as estrogen, primarily estriol, which promotes uterine growth and uteroplacental blood flow; progesterone, essential for maintaining the uterine lining and preventing contractions; human chorionic gonadotropin (hCG), which supports the corpus luteum; and human placental lactogen (hPL) or human chorionic somatomammotropin (hCS), which modulates maternal metabolism to provide nutrients for the fetus.

Choice C rationale

Placental development begins very early in pregnancy, around the second week post-fertilization, with the formation of the chorionic villi. By 8 weeks of gestation, the placenta is already well-established and actively performing its functions of hormone production and nutrient/waste exchange. Therefore, the statement that it has not yet begun to develop at 8 weeks indicates a significant misunderstanding of embryonic and fetal development timelines.

Choice D rationale

The placenta functions as the primary interface for maternal-fetal exchange. Its highly vascularized structure facilitates the efficient transfer of oxygen, glucose, amino acids, and other essential nutrients from the mother to the fetus. Concurrently, metabolic waste products, such as carbon dioxide and urea, are transported from the fetal circulation back to the maternal circulation for excretion, ensuring fetal homeostasis.

Choice A rationale

Severe headaches with nausea and visual disturbances are classic symptoms of migraine with aura, which is a contraindication for combined oral contraceptives. Estrogen in COCs can increase the risk of ischemic stroke in individuals with migraine with aura due to its prothrombotic effects on the cerebrovascular system. This elevated thrombotic risk makes COCs unsafe for these patients.

Choice B rationale

A history of breast cancer is an absolute contraindication for combined oral contraceptive pills. Many breast cancers are hormone-sensitive, meaning their growth can be stimulated by estrogen and progesterone, which are components of COCs. Introducing exogenous hormones could potentially accelerate the recurrence or progression of the disease.

Choice C rationale

While not an absolute contraindication, planning to conceive within 6-12 months makes combined oral contraceptives a less ideal choice. COCs can delay the return to fertility for a variable period after discontinuation, although this is usually temporary. Other methods, like barrier methods, might be more suitable for short-term contraception before planned conception.

Choice D rationale

Smoking significantly increases the risk of serious cardiovascular events, such as myocardial infarction and stroke, especially in women over 35 who use combined oral contraceptives. The estrogen component of COCs enhances coagulation and vascular reactivity, and smoking further exacerbates these risks, leading to a synergistic increase in thrombotic potential.