USMLE Step 2 Quiz
Practice Labor And Delivery in USMLE Step 2 with focused quiz questions that help you check what you know, review explanations, and build confidence with test-style prompts.
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A 29-year-old G3P2 woman is in the second stage of labor. Following delivery of the fetal head, it is noted to retract against the perineum. The infant's anterior shoulder cannot be delivered with gentle downward traction.
Which of the following is the most appropriate next step in management?
This quiz focuses on Labor And Delivery, giving you a quick way to practice the rules, question types, and explanations that matter most for USMLE Step 2.
Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.
A 29-year-old G3P2 woman is in the second stage of labor. Following delivery of the fetal head, it is noted to retract against the perineum. The infant's anterior shoulder cannot be delivered with gentle downward traction.
Which of the following is the most appropriate next step in management?
Explanation: The clinical scenario describes shoulder dystocia, an obstetric emergency where the anterior shoulder is impacted behind the pubic symphysis. The first-line intervention is the McRoberts maneuver, which involves hyperflexion of the mother's hips onto her abdomen. This maneuver flattens the sacral promontory and rotates the pubic symphysis superiorly, often freeing the impacted shoulder. Fundal pressure should be avoided as it can worsen the impaction. Other maneuvers, like delivery of the posterior arm, are considered if initial steps fail.
A 26-year-old primigravid woman at 40 weeks of gestation is being monitored for labor progression. She was admitted in the active phase of labor. Four hours ago, her cervical examination was 7 cm dilation, 100% effacement, and 0 station. An intrauterine pressure catheter is in place and shows contractions with an average of 220 Montevideo units (MVUs). A repeat examination now shows her cervix is unchanged at 7 cm. The fetal heart rate tracing is reassuring.
Which of the following is the most appropriate diagnosis?
Explanation: Arrest of the active phase of labor is diagnosed in a patient with a cervical dilation of 6 cm or more who has had ruptured membranes and no cervical change for 4 hours or more despite adequate contractions (≥200 MVUs), or no cervical change for 6 hours or more with inadequate contractions. This patient has had no cervical change for 4 hours with adequate contractions, meeting the criteria for active phase arrest, which is an indication for cesarean delivery.
A 28-year-old G2P1 woman has an uncomplicated spontaneous vaginal delivery of a healthy 3.5 kg infant. The infant is placed skin-to-skin on the mother's chest. The placenta has not yet delivered.
Which of the following interventions is most effective in reducing the risk of primary postpartum hemorrhage?
Explanation: Active management of the third stage of labor significantly reduces the risk of postpartum hemorrhage. This strategy consists of three components: 1) prophylactic administration of a uterotonic agent (most commonly oxytocin) shortly after the delivery of the infant, 2) controlled cord traction to facilitate placental delivery, and 3) uterine massage after the placenta has been delivered. Prophylactic oxytocin is the most critical component for preventing uterine atony, the leading cause of postpartum hemorrhage.
A 30-year-old G1P0 woman at 40 weeks is in active labor at 5 cm dilation. Her membranes ruptured spontaneously one hour ago with clear fluid. The electronic fetal monitor shows a baseline heart rate of 140 bpm with moderate variability. There are recurrent, abrupt decreases in the heart rate to 90 bpm, lasting approximately 30 seconds, with a rapid return to baseline. These decelerations occur with some, but not all, contractions.
These fetal heart rate findings are most likely caused by which of the following?
Explanation: The fetal heart rate pattern described is characteristic of variable decelerations. These are defined as an abrupt decrease in the FHR (onset to nadir <30 seconds) of at least 15 bpm, lasting at least 15 seconds but less than 2 minutes. They are variable in their timing relative to contractions and are caused by transient compression of the umbilical cord, which obstructs the umbilical vein and arteries. They are common after rupture of membranes.
A 38-year-old G4P3 woman at 38 weeks of gestation undergoes an artificial rupture of membranes to augment labor. The fetal vertex was at -2 station prior to the procedure. Immediately afterward, the fetal heart rate drops to 75 bpm and remains there. A sterile vaginal examination reveals a pulsating, soft structure in the vagina ahead of the fetal head.
Which of the following is the most appropriate immediate action?
Explanation: This patient has an umbilical cord prolapse, an obstetric emergency. The immediate goals are to relieve pressure on the cord to prevent fetal hypoxia by manually elevating the presenting fetal part with a gloved hand in the vagina and placing the mother in a position that uses gravity to move the fetus away from the pelvis, such as the knee-chest or deep Trendelenburg position. These maneuvers must be performed immediately while preparations for emergency cesarean delivery are made. Attempting to replace the cord is not recommended and may worsen compression.
A 29-year-old G1P0 woman at 38 weeks of gestation presents to the obstetric triage unit with a 12-hour history of intermittent, irregular lower abdominal cramping. The cramps have not increased in frequency or intensity. On examination, her cervix is 2 cm dilated, 50% effaced, thick, and posterior. A repeat examination 2 hours later shows no change in the cervix. The patient is able to talk through the cramps.
Which of the following is the most likely diagnosis?
Explanation: True labor is defined by the presence of regular uterine contractions that result in progressive cervical change (dilation and effacement). This patient's contractions are irregular and not increasing in intensity, and critically, there has been no cervical change over a 2-hour observation period. This clinical picture is characteristic of false labor, also known as Braxton Hicks contractions. Patients in false labor can be discharged home with instructions to return if contractions become regular, stronger, and closer together.
A 31-year-old G2P1 woman at 34 weeks of gestation presents to the hospital with a report of decreased fetal movement for the past day. An electronic fetal heart rate monitor is placed and shows a smooth, sine-wave-like undulating pattern with a frequency of 3-5 cycles per minute and an amplitude of 5-15 bpm. There are no accelerations.
This fetal heart rate pattern is most strongly associated with which of the following conditions?
Explanation: The described tracing is a sinusoidal pattern, which is an ominous Category III finding. It is characterized by a smooth, undulating wave form and is associated with a high risk of fetal morbidity and mortality. The most common underlying cause is severe fetal anemia, which may result from conditions such as Rh isoimmunization, vasa previa with bleeding, or fetomaternal hemorrhage. Its presence warrants immediate evaluation and likely emergent delivery.
A 24-year-old G1P0 woman at 39 weeks of gestation presents in active labor. Her membranes ruptured 20 hours ago. Her temperature is 38.5°C (101.3°F), pulse is 110/min, and she has uterine fundal tenderness on palpation. The fetal heart rate is 170/min. Her cervix is 7 cm dilated. A diagnosis of chorioamnionitis is made.
In addition to initiating broad-spectrum intravenous antibiotics, which of the following is the most appropriate next step in management?
Explanation: The management of chorioamnionitis includes broad-spectrum intravenous antibiotics (typically ampicillin and gentamicin) and prompt delivery to remove the source of infection. Since there are no contraindications to vaginal delivery, labor should be augmented with oxytocin to expedite delivery. Cesarean delivery is reserved for standard obstetric indications (e.g., arrest of labor, non-reassuring fetal status) and is not automatically required for chorioamnionitis. Corticosteroids are not indicated at term, and tocolytics are contraindicated as they would delay delivery.
A 20-year-old G1P0 woman at 40 weeks is in active labor. Her temperature is 38.3°C (100.9°F). The fetal heart rate tracing shows a persistent baseline of 175 bpm for the last 30 minutes, with moderate variability and occasional accelerations. There are no decelerations. The patient received an epidural 2 hours ago.
What is the most likely cause of the fetal heart rate finding?
Explanation: Fetal tachycardia is defined as a baseline heart rate greater than 160 bpm for at least 10 minutes. The most common cause of fetal tachycardia is maternal fever, which increases both maternal and fetal metabolic rates. Other causes include maternal dehydration, chorioamnionitis (which also causes fever), certain medications, and fetal hypoxia. In this case, with moderate variability and accelerations present, hypoxia is less likely, and the maternal fever is the most probable explanation.
A 29-year-old G1P0 woman at 41 weeks of gestation is undergoing labor induction with an intravenous oxytocin infusion. The electronic monitor shows 7 contractions in a 10-minute period, each lasting 60-70 seconds. The fetal heart rate tracing shows recurrent late decelerations.
Which of the following is the most appropriate initial action?
Explanation: The patient is experiencing uterine tachysystole (more than 5 contractions in 10 minutes), which is a potential side effect of oxytocin. The excessive contractions are compromising uteroplacental blood flow, leading to late decelerations. The most appropriate initial action is to discontinue the oxytocin infusion to reduce uterine activity. Other intrauterine resuscitation measures, such as maternal repositioning and IV fluids, should also be initiated, but stopping the offending agent is the priority.
During a normal, uncomplicated vaginal delivery, the fetal head has been delivered and has undergone external rotation, aligning the fetal shoulders in an anteroposterior diameter. The delivering provider applies gentle downward traction to the fetal head.
This maneuver is performed to facilitate the delivery of which of the following?
Explanation: This question describes the sequence of events in a normal delivery. After delivery and external rotation of the head, the anterior shoulder lies just behind the maternal pubic symphysis. Gentle downward traction on the head allows the anterior shoulder to slip under the pubic symphysis and deliver. Once the anterior shoulder is delivered, gentle upward traction is then applied to deliver the posterior shoulder.
A 33-year-old G2P1 woman at 37 weeks of gestation presents to the emergency department with an episode of painless, bright red vaginal bleeding. She has not had contractions. Her vital signs are stable. A transabdominal ultrasound is performed, which confirms a complete placenta previa. The fetal heart rate is 140 bpm with moderate variability.
Which of the following is the most appropriate mode of delivery for this patient?
Explanation: A complete placenta previa, where the placenta entirely covers the internal cervical os, is an absolute contraindication to labor and vaginal delivery. Attempting a vaginal delivery would cause catastrophic hemorrhage as the cervix dilates and effaces, disrupting the placental attachment. Therefore, the definitive management is a scheduled cesarean delivery, typically performed at 36-37 weeks of gestation to balance the risks of prematurity against the risk of hemorrhage with the onset of labor.
A 34-year-old primigravid woman with a singleton gestation at term has been in the second stage of labor for 3.5 hours. She has an effective epidural for analgesia. The fetal head has been at +1 station in the occiput anterior position for the last 2 hours without descent despite good maternal pushing efforts. The fetal heart rate tracing remains reassuring.
This patient's labor is best described as which of the following?
Explanation: Arrest of the second stage of labor is diagnosed based on the duration of pushing without progress. In a nulliparous woman with an epidural, arrest is diagnosed after 3 or more hours of pushing with no descent of the fetal presenting part. This patient has been pushing for 3.5 hours with no progress for the last 2 hours, meeting the criteria for second-stage arrest. Management options include operative vaginal delivery or cesarean delivery.
Immediately following a spontaneous vaginal delivery, the provider applies strong traction to the umbilical cord to deliver the placenta. The patient suddenly complains of severe abdominal pain and develops hypotension with a heart rate of 130/min. A large, boggy, reddish mass is visible at the introitus. The uterine fundus is no longer palpable on abdominal examination.
What is the most appropriate initial step in management?
Explanation: This patient has an acute uterine inversion, a rare but life-threatening obstetric emergency often caused by excessive cord traction on a fundally implanted placenta. The initial management is to attempt immediate manual replacement of the uterus by pushing the fundus back through the cervix with the palm of the hand. This should be done before the cervix contracts and traps the inverted uterus. Uterotonics like oxytocin should only be administered after the uterus is successfully replaced. If manual replacement fails, uterine relaxants (e.g., terbutaline, nitroglycerin) may be needed before another attempt, followed by surgery if unsuccessful.
A 26-year-old woman has just undergone a spontaneous vaginal delivery of a healthy infant. A few minutes later, the physician observes a sudden gush of blood from the vagina, notes that the umbilical cord appears to lengthen, and feels the uterine fundus become firm and rise in the abdomen.
These clinical findings are most indicative of which of the following events?
Explanation: These are the three classic clinical signs of placental separation, which occurs during the third stage of labor. The gush of blood is from the retroplacental space, the cord lengthens as the placenta descends into the lower uterine segment, and the uterus contracts, becomes firm, and rises (Calkin's sign). These signs indicate that the placenta is ready to be delivered, usually with gentle, controlled cord traction.
A 22-year-old primigravid woman at 39 weeks of gestation is in the active phase of labor with her cervix dilated to 6 cm. She reports her pain as 9 out of 10 during contractions and requests pain relief. She is hemodynamically stable, her platelet count is 200,000/mm³, and she has no known allergies. She desires the most effective pain relief available.
Which of the following is the most appropriate and effective method for pain control in this patient?
Explanation: Neuraxial analgesia, most commonly an epidural, is considered the most effective method for pain relief during labor. It provides excellent sensory blockade while allowing the patient to remain awake and participative. Intravenous opioids like fentanyl can be used but provide less complete pain relief and can cause maternal and neonatal respiratory depression. A pudendal block is typically used for perineal analgesia during the second stage of labor and delivery, not for contraction pain. Nitrous oxide provides moderate relief but is less effective than an epidural.
A 32-year-old G2P1 woman is fully dilated and has been pushing for 2 hours without an epidural. The fetal head is at +2 station in an occiput anterior position. The patient is becoming exhausted, and her pushing efforts are diminishing. The fetal heart rate tracing has developed recurrent late decelerations. The obstetrician is skilled in operative deliveries.
Which of the following is the most appropriate next step in management?
Explanation: This patient has an indication for operative vaginal delivery, which includes a prolonged second stage with maternal exhaustion and a non-reassuring fetal heart rate pattern. The prerequisites are met: cervix is fully dilated, membranes are ruptured, the fetal head is engaged (+2 station), the position is known (occiput anterior), and there is no evidence of cephalopelvic disproportion. An assisted vaginal delivery (with forceps or vacuum) is typically faster than performing a cesarean section at this stage and is therefore the preferred approach to expedite delivery.
A 32-year-old G2P1 woman at 40 weeks of gestation is in active labor with an epidural in place. Her cervix is 8 cm dilated. The fetal heart rate (FHR) monitor shows a baseline of 130 bpm with minimal variability. For the past 30 minutes, there have been three decelerations that begin after the peak of a contraction and nadir at 100 bpm, with a slow return to baseline. The patient's blood pressure is 105/65 mmHg.
Which of the following is the most appropriate initial step in management?
Explanation: The fetal heart rate tracing describes recurrent late decelerations, which are indicative of uteroplacental insufficiency. The initial management of this finding involves intrauterine resuscitation measures. These include maternal repositioning (e.g., left lateral position) to improve uterine blood flow, administration of intravenous fluids to correct maternal hypotension, and supplemental oxygen. If these measures fail to resolve the non-reassuring tracing, delivery may be indicated.
A 25-year-old G1P0 woman at 41 weeks of gestation is fully dilated. Her fetal heart rate (FHR) tracing has shown a persistent baseline of 105 bpm with absent variability and recurrent late decelerations for the last 20 minutes. Intrauterine resuscitation measures, including maternal repositioning, intravenous fluids, and supplemental oxygen, have not resulted in any improvement in the FHR tracing.
Which of the following is the most appropriate next step in management?
Explanation: The described fetal heart rate tracing (bradycardia, absent variability, and recurrent late decelerations) is a Category III tracing, which is abnormal and strongly predictive of abnormal fetal acid-base status. When such a tracing does not resolve with intrauterine resuscitation measures, prompt delivery is indicated. Since the patient is fully dilated, an operative vaginal delivery could be considered if the criteria are met and delivery is imminent; however, given the ominous tracing, immediate cesarean delivery is the safest and most definitive management.
A 26-year-old primigravid woman at 40 weeks' gestation is admitted in spontaneous labor. On arrival her cervix is 4 cm dilated, 90 percent effaced, and the fetal head is at –1 station. External tocodynamometry shows contractions every 8 minutes, each lasting 25 seconds. Four hours later the cervix remains unchanged despite the patient's ambulation. Which of the following is the most appropriate next step in management?
Explanation: When evaluating labor progress, you need to understand the stages of labor and what constitutes normal versus abnormal progress. This question tests your knowledge of labor dystocia and appropriate interventions during the active phase. This patient presents with inadequate uterine activity - contractions every 8 minutes lasting only 25 seconds are insufficient for normal labor progression. Normal active labor requires contractions every 2-3 minutes, lasting 45-60 seconds, with adequate intensity. When cervical change stalls despite 4 hours in active labor, the most likely cause is inadequate uterine contractility, making oxytocin augmentation the appropriate first intervention. Choice A is correct because oxytocin will strengthen and coordinate contractions, addressing the underlying problem of inadequate uterine activity. Choice B (artificial rupture of membranes) might be considered as an adjunct, but won't address the fundamental issue of weak, infrequent contractions. AROM alone is unlikely to resolve this labor dystocia. Choice C (cesarean delivery) is premature. You haven't attempted to correct the inadequate uterine activity first. Cesarean for arrest of active phase is indicated only after adequate uterine activity has been established and cervical change still doesn't occur. Choice D (discharge home) is inappropriate since she's already in active labor at 4 cm dilation. Once active labor begins, you don't send patients home. Remember: Before diagnosing labor dystocia, always ensure adequate uterine activity first. The hierarchy is: optimize contractions → consider AROM if needed → cesarean only if conservative measures fail.