A pregnant woman undergoes a triple/quadruple screen at 16 to 18 weeks' gestation. What would the nurse suspect if the woman's alpha-fetoprotein (AFP) level is decreased?

Choice A Reason: This is incorrect because marijuana is a psychoactive substance that affects the central nervous system and can cause euphoria, relaxation, altered perception, and impaired memory. It does not cause tachycardia, hypertension, or vasoconstriction in pregnant women or their fetuses.

Choice B Reason: This is correct because cocaine is a stimulant substance that affects the cardiovascular system and can cause tachycardia, hypertension, vasoconstriction, arrhythmias, and ischemia in pregnant women or their fetuses. It can also increase the risk of placental abruption, preterm labor, intrauterine growth restriction, and fetal death.

Choice C Reason: This is incorrect because nicotine is a stimulant substance that affects the respiratory system and can cause bronchodilation, increased heart rate, and increased blood pressure in pregnant women or their fetuses. However, it does not cause vasoconstriction, but rather vasodilation.

Choice D Reason: This is incorrect because caffeine is a stimulant substance that affects the central nervous system and can cause alertness, insomnia, anxiety, and increased urine output in pregnant women or their fetuses. It does not cause tachycardia, hypertension, or vasoconstriction in moderate doses.

Choice E Reason: This is incorrect because heroin is an opioid substance that affects the central nervous system and can cause euphoria, sedation, analgesia, and respiratory depression in pregnant women or their fetuses. It does not cause tachycardia, hypertension, or vasoconstriction.

Choice A Reason: This is incorrect because hemoconcentration by hypertension is a condition where the blood volume decreases and the blood pressure increases, leading to a higher hemoglobin level. A normal hemoglobin level for a pregnant woman in her second trimester is 10.5 to 14 g/dL. A hemoglobin level of 11 g/dL is within the normal range, not indicative of hemoconcentration.

Choice B Reason: This is incorrect because a multiple gestation pregnancy is a pregnancy with more than one fetus, such as twins or triplets. A multiple gestation pregnancy can cause a lower hemoglobin level due to increased blood volume and increased demand for iron. A hemoglobin level of 11 g/dL is not suggestive of a multiple gestation pregnancy.

Choice C Reason: This is incorrect because greater-than-expected weight gain is not directly related to the hemoglobin level. Weight gain during pregnancy depends on various factors such as pre-pregnancy weight, nutrition, physical activity, and genetics. A hemoglobin level of 11 g/dL does not reflect the weight status of the pregnant client.

Choice D Reason: This is correct because iron-deficiency anemia is a common type of anemia that occurs when the body does not have enough iron to produce enough red blood cells. Iron-deficiency anemia can cause a low hemoglobin level and affect the oxygen delivery to the tissues and the fetus. A hemoglobin level of 11 g/dL may indicate iron-deficiency anemia, especially if the client has other symptoms such as fatigue, weakness, pale skin, or cravings for non-food items. The nurse should confirm the diagnosis with further tests and recommend iron supplements and dietary changes to treat the condition.