OB/NB SU Exam 3 Questions and Verified
Answers with Rationale | Latest Edition
2026/2027
QUESTION 1
A nurse is caring for a client at 34 weeks gestation who is
admitted in preterm labor. The primary healthcare provider
prescribes nifedipine. Which of the following mechanisms
explains the primary action of this medication in this clinical
scenario?
A. It stimulates beta-2 adrenergic receptors to relax bronchial
smooth muscle.
B. It blocks calcium ion influx into myometrial cells to inhibit
uterine contractions.
C. It acts directly on the posterior pituitary to suppress oxytocin
synthesis.
D. It binds to prostaglandin receptors to reduce inflammatory
mediators.
CORRECT ANSWER: B
RATIONALE:
Nifedipine is a calcium channel blocker commonly used as a
tocolytic agent. By blocking calcium influx into smooth muscle
cells, it prevents the interaction between actin and myosin,
,thereby relaxing the myometrium and halting preterm uterine
contractions.
QUESTION 2
A nurse is monitoring a client receiving a continuous infusion of
magnesium sulfate for preeclampsia. Which of the following
assessment findings indicates the onset of severe magnesium
toxicity requiring immediate intervention?
A. Respiratory rate of 10 breaths per minute
B. Blood pressure of 130/86 mm Hg
C. Patellar deep tendon reflexes rated as 2+
D. Urinary output of 50 mL per hour
CORRECT ANSWER: A
RATIONALE:
Depression of the respiratory center is a hallmark sign of
advanced magnesium toxicity. A respiratory rate below 12
breaths per minute indicates dangerous toxicity levels, requiring
immediate cessation of the infusion and administration of
calcium gluconate. Reflexes rated 2+ and adequate urine output
are normal therapeutic findings.
QUESTION 3
A nurse is assessing a postpartum client who gave birth to a
macrosomic infant 30 minutes ago. The nurse notes the client's
fundus is boggy, midline, and high, with a continuous trickle of
,bright red blood. Which of the following is the most likely cause
of this postpartum hemorrhage?
A. Uterine atony
B. Retained placental fragments
C. Cervical laceration
D. Uterine inversion
CORRECT ANSWER: A
RATIONALE:
Uterine atony is the most common cause of early postpartum
hemorrhage, characterized by a relaxed, boggy uterus that fails
to contract and constrict maternal blood vessels at the placental
site. Risk factors include macrosomia, polyhydramnios, and
multiple gestation.
QUESTION 4
A nurse is providing discharge instructions to a postpartum
client who is formula feeding her infant. Which of the following
statements indicates a correct understanding of lactation
suppression measures?
A. I should pump my breasts every four hours until the milk
supply completely dries up.
B. I will apply warm compresses and massage my breasts
vigorously during showers.
, C. I will wear a tight, supportive bra continuously and apply ice
packs to my breasts.
D. I should restrict my daily fluid intake to less than 500 mL to
stop milk production.
CORRECT ANSWER: C
RATIONALE:
Wearing a supportive bra 24 hours a day and applying cold
packs helps reduce discomfort and suppress lactation without
stimulating prolactin release. Pumping, warm compresses, and
breast massage stimulate milk production, while fluid restriction
is ineffective and dangerous.
QUESTION 5
A nurse is evaluating a fetal heart rate monitor strip and
observes uniform decelerations that mirror the shape of the
uterine contractions, with the lowest point of the deceleration
occurring at the peak of the contraction. Which of the following
actions is most appropriate?
A. Administer oxygen via non-rebreather mask at 10 L/min.
B. Stop the oxytocin infusion immediately and reposition the
client.
C. Document the finding as a normal, reassuring variant
requiring no intervention.
D. Prepare the client for an emergency cesarean delivery.
Answers with Rationale | Latest Edition
2026/2027
QUESTION 1
A nurse is caring for a client at 34 weeks gestation who is
admitted in preterm labor. The primary healthcare provider
prescribes nifedipine. Which of the following mechanisms
explains the primary action of this medication in this clinical
scenario?
A. It stimulates beta-2 adrenergic receptors to relax bronchial
smooth muscle.
B. It blocks calcium ion influx into myometrial cells to inhibit
uterine contractions.
C. It acts directly on the posterior pituitary to suppress oxytocin
synthesis.
D. It binds to prostaglandin receptors to reduce inflammatory
mediators.
CORRECT ANSWER: B
RATIONALE:
Nifedipine is a calcium channel blocker commonly used as a
tocolytic agent. By blocking calcium influx into smooth muscle
cells, it prevents the interaction between actin and myosin,
,thereby relaxing the myometrium and halting preterm uterine
contractions.
QUESTION 2
A nurse is monitoring a client receiving a continuous infusion of
magnesium sulfate for preeclampsia. Which of the following
assessment findings indicates the onset of severe magnesium
toxicity requiring immediate intervention?
A. Respiratory rate of 10 breaths per minute
B. Blood pressure of 130/86 mm Hg
C. Patellar deep tendon reflexes rated as 2+
D. Urinary output of 50 mL per hour
CORRECT ANSWER: A
RATIONALE:
Depression of the respiratory center is a hallmark sign of
advanced magnesium toxicity. A respiratory rate below 12
breaths per minute indicates dangerous toxicity levels, requiring
immediate cessation of the infusion and administration of
calcium gluconate. Reflexes rated 2+ and adequate urine output
are normal therapeutic findings.
QUESTION 3
A nurse is assessing a postpartum client who gave birth to a
macrosomic infant 30 minutes ago. The nurse notes the client's
fundus is boggy, midline, and high, with a continuous trickle of
,bright red blood. Which of the following is the most likely cause
of this postpartum hemorrhage?
A. Uterine atony
B. Retained placental fragments
C. Cervical laceration
D. Uterine inversion
CORRECT ANSWER: A
RATIONALE:
Uterine atony is the most common cause of early postpartum
hemorrhage, characterized by a relaxed, boggy uterus that fails
to contract and constrict maternal blood vessels at the placental
site. Risk factors include macrosomia, polyhydramnios, and
multiple gestation.
QUESTION 4
A nurse is providing discharge instructions to a postpartum
client who is formula feeding her infant. Which of the following
statements indicates a correct understanding of lactation
suppression measures?
A. I should pump my breasts every four hours until the milk
supply completely dries up.
B. I will apply warm compresses and massage my breasts
vigorously during showers.
, C. I will wear a tight, supportive bra continuously and apply ice
packs to my breasts.
D. I should restrict my daily fluid intake to less than 500 mL to
stop milk production.
CORRECT ANSWER: C
RATIONALE:
Wearing a supportive bra 24 hours a day and applying cold
packs helps reduce discomfort and suppress lactation without
stimulating prolactin release. Pumping, warm compresses, and
breast massage stimulate milk production, while fluid restriction
is ineffective and dangerous.
QUESTION 5
A nurse is evaluating a fetal heart rate monitor strip and
observes uniform decelerations that mirror the shape of the
uterine contractions, with the lowest point of the deceleration
occurring at the peak of the contraction. Which of the following
actions is most appropriate?
A. Administer oxygen via non-rebreather mask at 10 L/min.
B. Stop the oxytocin infusion immediately and reposition the
client.
C. Document the finding as a normal, reassuring variant
requiring no intervention.
D. Prepare the client for an emergency cesarean delivery.
