Which compound would the nurse have readily available for a client who is receiving magnesium sulfate to treat severe preeclampsia?

Choice A Reason: This is incorrect because sickle-cell anemia is a genetic disorder that affects the shape and function of red blood cells. It does not affect the AFP level, which is a protein produced by the fetus and placenta. Sickle-cell anemia can be detected by other prenatal tests, such as hemoglobin electrophoresis or DNA analysis.

Choice B Reason: This is incorrect because cardiac defects are structural abnormalities of the heart or blood vessels that affect the blood flow and oxygen delivery to the fetus. They may cause an increased AFP level, not a decreased one, as they can lead to fetal distress or edema. Cardiac defects can be detected by other prenatal tests, such as fetal echocardiography or ultrasound.

Choice C Reason: This is correct because Down syndrome is a chromosomal disorder that results from an extra copy of chromosome 21. It causes various physical and mental developmental delays and defects in the fetus. It is associated with a decreased AFP level, as well as decreased levels of human chorionic gonadotropin (hCG) and unconjugated estriol (uE3). Down syndrome can be confirmed by other prenatal tests, such as amniocentesis or chorionic villus sampling (CVS).

Choice D Reason: This is incorrect because respiratory disorders are problems that affect the breathing and gas exchange of the fetus. They may cause an increased AFP level, not a decreased one, as they can lead to fetal distress or edema. Respiratory disorders can be detected by other prenatal tests, such as fetal biophysical profile (BPP) or nonstress test (NST).

Choice A: Striae gravidarum are stretch marks that appear on the abdomen, breasts, or thighs during pregnancy. They are caused by the tearing of the connective tissue in the dermis due to rapid growth or weight gain.

Choice B: Linea nigra is a dark vertical line that runs from the umbilicus to the pubic area. It is caused by increased melanin production due to hormonal changes during pregnancy. This is the correct choice because it matches the description in the question.

Choice C: Vascular spiders are dilated blood vessels that appear on the skin as red or purple spider-like lesions. They are caused by increased estrogen levels and blood volume during pregnancy. They are usually found on the face, neck, chest, or arms.

Choice D: Melasma is a condition that causes brown or gray patches on the face, especially on the forehead, cheeks, nose, or upper lip. It is caused by increased melanin production due to sun exposure and hormonal changes during pregnancy. It is also known as chloasma or the mask of pregnancy.