A nurse is caring for a client who is at 22 weeks of gestation and has been unable to control her gestational diabetes mellitus with diet and exercise. The nurse should anticipate a prescription from the provider for which of the following medications for the client?

Choice A reason: Painless red vaginal bleeding is the most characteristic finding of placenta previa, which is a condition where the placenta covers the cervical opening and can cause bleeding in the third trimester. Painless red vaginal bleeding occurs because the placenta is detached from the lower uterine segment as the cervix dilates or effaces, and the blood vessels are torn. The bleeding can be mild or severe, and it can recur or persist until delivery.

Choice B reason: Intermittent abdominal pain following passage of bloody mucus is not a finding that supports placenta previa, but rather a finding that suggests normal labor or preterm labor. Intermittent abdominal pain is caused by uterine contractions, which can be regular or irregular, and can increase in frequency, duration, and intensity. Bloody mucus is the mucus plug that is expelled from the cervix as it dilates or effaces, and it can be tinged with blood or streaked with blood.

Choice C reason: Increasing abdominal pain with a nonrelaxed uterus is not a finding that supports placenta previa, but rather a finding that indicates abruptio placentae, which is a premature separation of the placenta from the uterine wall. Increasing abdominal pain is caused by the bleeding and the hematoma formation behind the placenta, which can compress the uterine muscle and the nerve endings. Nonrelaxed uterus is a sign of uterine hypertonicity, which can reduce the blood flow and the oxygen delivery to the fetus.

Choice D reason: Abdominal pain with scant red vaginal bleeding is not a finding that supports placenta previa, but rather a finding that suggests ectopic pregnancy, which is a condition where the fertilized ovum implants outside the uterine cavity, usually in the fallopian tube. Abdominal pain is caused by the rupture of the tube and the bleeding into the peritoneal cavity, which can irritate the diaphragm and the abdominal wall. Scant red vaginal bleeding is a sign of implantation bleeding, which can occur when the fertilized ovum attaches to the tube wall.

Choice A reason: This statement is incorrect, as it is not the definition of polyhydramnios, but rather a possible cause of it. Polyhydramnios is a condition where the amniotic fluid volume exceeds 2,000 mL at term, or the amniotic fluid index (AFI) is greater than 25 cm. Polyhydramnios can occur in multiple pregnancies, as the fetuses produce more urine and fluid than a single fetus.

Choice B reason: This statement is incorrect, as it is not the definition of polyhydramnios, but rather a possible complication of it. Polyhydramnios can cause fetal anomalies, such as esophageal atresia, anencephaly, or neural tube defects, which impair the swallowing or absorption of the amniotic fluid. Polyhydramnios can also cause fetal growth restriction or distress, as the excess fluid can compress the umbilical cord or the placenta, and reduce the blood flow and oxygen delivery to the fetus.

Choice C reason: This statement is correct, as it is the definition of polyhydramnios, which is a condition where the amniotic fluid volume exceeds 2,000 mL at term, or the amniotic fluid index (AFI) is greater than 25 cm. Polyhydramnios can be diagnosed by ultrasound, and it can cause maternal and fetal complications, such as preterm labor, premature rupture of membranes, placental abruption, or cord prolapse.

Choice D reason: This statement is incorrect, as it is not the definition of polyhydramnios, but rather a marker of fetal anomalies. Alpha-fetoprotein (AFP) is a protein that is produced by the fetus, and it can be measured in the maternal serum or the amniotic fluid. An elevated level of AFP in the amniotic fluid can indicate fetal anomalies, such as neural tube defects, abdominal wall defects, or renal anomalies, which can cause polyhydramnios.