Which of the following is the priority nursing action for a client at 33 weeks of gestation with a diagnosis of placenta previa?

Choice A reason:
Magnesium sulfate is used in the management of severe preeclampsia primarily for seizure prophylaxis. One of the key side effects of magnesium sulfate is its impact on neuromuscular transmission, leading to diminished deep-tendon reflexes as serum magnesium levels rise. The therapeutic range for anticonvulsant prophylaxis is typically between 5-8 mg/dL. Reflexes may begin to diminish when serum levels reach 8-12 mg/dL, indicating potential magnesium toxicity. Therefore, diminished reflexes are a warning sign to reassess the infusion rate and possibly reduce or discontinue the medication.

Choice B reason:
A respiratory rate of 16 breaths per minute falls within the normal adult range and suggests that the client's respiratory system is not being adversely affected by the magnesium sulfate infusion. Respiratory rate is a critical parameter to monitor during magnesium sulfate therapy, as respiratory depression is a serious side effect of magnesium toxicity. Maintaining a normal respiratory rate indicates that it is safe to continue the infusion at the current rate.

Choice C reason:
While a urine output of 50 mL/hr is on the lower end of the normal range, it is still considered adequate for most adults. In the setting of magnesium sulfate therapy for severe preeclampsia, maintaining adequate urine output is essential for ensuring that the kidneys can excrete the magnesium to prevent accumulation and toxicity. If urine output decreases significantly, it may necessitate reevaluation of the infusion rate or additional interventions to support renal function.

Choice D reason:
A heart rate of 56 beats per minute is slightly bradycardic but may not be clinically significant if the client is asymptomatic. However, magnesium has a direct effect on cardiac function, and high levels can lead to bradycardia and other cardiac conduction abnormalities. It is important to monitor the client's heart rate and rhythm during magnesium sulfate therapy to detect any early signs of cardiac involvement due to magnesium toxicity.

Choice a reason:
Increasing abdominal pain with a nonrelaxed uterus is not typically indicative of placenta previa. This symptom could suggest other complications such as uterine rupture or placental abruption, which are serious conditions requiring immediate medical attention.

Choice b reason:
Abdominal pain with scant red vaginal bleeding is also not a classic sign of placenta previa. While vaginal bleeding can occur in placenta previa, it is usually not associated with abdominal pain. Pain accompanied by bleeding is more suggestive of other obstetric emergencies.

Choice c reason:
Painless red vaginal bleeding is a hallmark sign of placenta previa. In placenta previa, the placenta covers the cervical os either partially or completely, leading to bleeding when the lower part of the uterus stretches and thins as part of the preparation for labor. This bleeding is typically sudden and painless and can range from light to heavy.

Choice d reason:
Intermittent abdominal pain following the passage of bloody mucus is not characteristic of placenta previa. This symptom could be associated with the normal process of losing the mucus plug as labor approaches or could indicate other conditions but is not specific to placenta previa.