A nurse is providing prenatal care to a pregnant client. At which time would the nurse expect to screen the client for group B streptococcus infection?

Choice A: Hemodilution of pregnancy is a normal physiological phenomenon that occurs when the plasma volume increases more than the red blood cell mass, resulting in a lower hemoglobin concentration. The normal hemoglobin range for pregnant women in the second trimester is 10.5 to 14 g/dL.

Choice B: A multiple gestation pregnancy may cause a higher hemoglobin level due to increased erythropoietin production by the placenta. The normal hemoglobin range for pregnant women with twins in the second trimester is 12 to 16 g/dL.

Choice C: Greater-than-expected weight gain is not related to hemoglobin level. Weight gain during pregnancy depends on various factors such as pre-pregnancy weight, nutrition, activity level, and fetal growth.

Choice D: Iron-deficiency anemia is a condition where the hemoglobin level is below the normal range due to inadequate iron intake or absorption, blood loss, or increased iron demand. The signs and symptoms of iron-deficiency anemia include fatigue, pallor, weakness, shortness of breath, and pica.

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).