Obstetric Nurse Test Obstetric Nurse Pharmacology in Obstetrics 5 — Questions and Answers
Question 1: A nurse is administering Rh immune globulin (RhoGAM) to an Rh-negative postpartum patient. Within what timeframe must it be given to be effective?
- Within 24 hours of delivery
- Within 48 hours of delivery
- Within 72 hours of delivery (Correct answer)
- Within 96 hours of delivery
Correct answer: Within 72 hours of delivery
RhoGAM must be administered within 72 hours of delivery to prevent Rh sensitization by destroying fetal Rh-positive cells before the maternal immune system mounts a response.
Question 2: A laboring patient received IV morphine 8 mg 1 hour ago. She is now 10 cm and begins pushing. What is the nurse's priority concern regarding the neonate?
- Neonatal jaundice within 24 hours
- Neonatal respiratory depression at delivery (Correct answer)
- Neonatal hypoglycemia in the first hour
- Neonatal seizures from opioid withdrawal
Correct answer: Neonatal respiratory depression at delivery
Morphine administered close to delivery crosses the placenta and can cause neonatal respiratory depression; naloxone and resuscitation equipment must be immediately available.
Question 3: Which medication is used prophylactically in a patient with a history of preeclampsia to reduce recurrence risk in the current pregnancy?
- Low-dose aspirin (81 mg daily) (Correct answer)
- Nifedipine 30 mg daily
- Metformin 500 mg daily
- Heparin 5,000 units subcutaneously twice daily
Correct answer: Low-dose aspirin (81 mg daily)
Low-dose aspirin started before 16 weeks gestation significantly reduces the risk of preeclampsia recurrence by inhibiting thromboxane A2-mediated platelet aggregation and vasoconstriction.
Question 4: A patient is receiving IV magnesium sulfate at 2 g/hr. She becomes confused and her deep tendon reflexes are absent. Serum magnesium is 10 mEq/L. What is the nurse's immediate action?
- Reduce the infusion rate by 50%
- Stop the infusion and administer calcium gluconate 1 g IV (Correct answer)
- Administer sodium bicarbonate IV
- Increase IV fluid rate to promote renal excretion
Correct answer: Stop the infusion and administer calcium gluconate 1 g IV
Loss of deep tendon reflexes and confusion indicate severe magnesium toxicity; the infusion must be stopped immediately and calcium gluconate administered as the antidote.
Question 5: Which class of medication is contraindicated in all trimesters of pregnancy due to risk of fetal renal dysgenesis and oligohydramnios?
- ACE inhibitors (Correct answer)
- Beta blockers
- Calcium channel blockers
- Thiazide diuretics
Correct answer: ACE inhibitors
ACE inhibitors are absolutely contraindicated in pregnancy because they impair fetal renal perfusion, leading to renal dysgenesis, oligohydramnios, and fetal/neonatal death.
Question 6: A nurse is giving erythromycin ophthalmic ointment to a newborn. What is the primary purpose of this prophylaxis?
- Prevent herpes simplex ophthalmia
- Prevent gonococcal and chlamydial ophthalmia neonatorum (Correct answer)
- Prevent chemical conjunctivitis from amniotic fluid
- Prevent cytomegalovirus eye infection
Correct answer: Prevent gonococcal and chlamydial ophthalmia neonatorum
Erythromycin ophthalmic ointment is mandated in most U.S. states to prevent ophthalmia neonatorum caused by Neisseria gonorrhoeae and Chlamydia trachomatis acquired during passage through an infected birth canal.
Question 7: A patient with preeclampsia with severe features has a magnesium sulfate infusion running. The nurse notes urine output of 15 mL over the past hour. What is the priority action?
- Continue the infusion and reassess in 30 minutes
- Notify the provider immediately and prepare to hold or reduce the dose (Correct answer)
- Increase IV fluid rate to 200 mL/hr to improve urine output
- Administer furosemide 20 mg IV per standing orders
Correct answer: Notify the provider immediately and prepare to hold or reduce the dose
Magnesium is renally excreted, and oliguria (less than 25 mL/hr) increases the risk of toxic accumulation; the provider must be notified to reassess the dose.
Obstetric Nurse Test Obstetric Nurse Pharmacology in Obstetrics 5
A nurse is administering Rh immune globulin (RhoGAM) to an Rh-negative postpartum patient.
Within what timeframe must it be given to be effective?