A 24-year-old woman, gravida 1, at 35 weeks gestation is admitted to the hospital with regular contractions and pelvic pressure for the last 5 hours. Her pregnancy has been uncomplicated and she has attended many prenatal appointments and followed the physician's advice about screening for diseases, laboratory testing, diet, and exercise. She has had no history of fluid leakage or bleeding. At the hospital, her temperature is 37.2°C (99.0°F), blood pressure is 108/60 mm Hg, pulse is 88/min, and respirations are 16/min. Cervical examination shows 60% effacement and 5 cm dilation with intact membranes. Cardiotocography shows a contraction amplitude of 220 MVU in 10 minutes. Which of the following is the most appropriate pharmacotherapy at this time?

No pharmacotherapy at this time

A 33-year-old woman, gravida 2, para 1, at 26 weeks' gestation comes to the emergency department because of frequent contractions. The contractions are 40 seconds each, occurring every 2 minutes, and increasing in intensity. Her first child was delivered by lower segment transverse cesarean section because of a nonreassuring fetal heart rate. Her current medications include folic acid and a multivitamin. Her temperature is 36.9°C (98.4°F), heart rate is 88/min, and blood pressure is 126/76 mm Hg. Contractions are felt on the abdomen. There is clear fluid in the vulva and the introitus. The cervix is dilated to 5 cm, 70% effaced, and station of the head is -2. A fetal ultrasound shows polyhydramnios, a median cleft lip, and fused thalami. The corpus callosum, 3rd ventricle, and lateral ventricles are absent. The spine shows no abnormalities and there is a four chamber heart. Which of the following is the most appropriate next step in management?

Perform dilation and evacuation

A 24-year-old woman at 36 weeks pregnant presents to the emergency department with a headache and abdominal pain. The woman has no known past medical history and has inconsistently followed up with an obstetrician for prenatal care. Her temperature is 98.5°F (36.9°C), blood pressure is 163/101 mmHg, pulse is 90/min, respirations are 16/min, and oxygen saturation is 97% on room air. Prior to performing the physical exam, the patient experiences a seizure, which resolves after 60 seconds. Which of the following is the best management for this patient?

Diazepam, magnesium, and continuous monitoring

Magnesium and continuous monitoring

Nifedipine and cesarean section

A 30-year-old woman, gravida 2, para 1, at 38 weeks' gestation comes to the hospital for regular, painful contractions that have been increasing in frequency. Her pregnancy has been complicated by gestational diabetes treated with insulin. Pelvic examination shows the cervix is 50% effaced and 4 cm dilated; the vertex is at -1 station. Ultrasonography shows no abnormalities. A tocometer and Doppler fetal heart monitor are placed on the patient's abdomen. The fetal heart rate monitoring strip shows a baseline heart rate of 145/min with a variability of ≥ 15/min. Within a 20-minute recording, there are 7 uterine contractions, 4 accelerations, and 3 decelerations that have a nadir occurring within half a minute. The decelerations occur at differing intervals relative to the contractions. Which of the following is the most appropriate next step in the management of this patient?

Placement of fetal scalp electrode

A 37-year-old woman presents with an inability to void in the hours after giving birth to her first child via vaginal delivery. Her delivery involved the use of epidural anesthesia as well as pelvic trauma from the use of forceps. She is currently experiencing urinary leakage and complains of increased lower abdominal pressure. Which of the following is the most appropriate treatment for this patient’s condition?

Pelvic floor muscle strengthening

A 27-year old primigravid woman at 37 weeks' gestation comes to the emergency department because of frequent contractions for 4 hours. Her pregnancy has been complicated by hyperemesis gravidarum which subsided in the second trimester. The contractions occur every 10–15 minutes and have been increasing in intensity and duration since onset. Her temperature is 37.1°C (98.8°F), pulse is 110/min, and blood pressure is 140/85 mm Hg. Uterine contractions are felt on palpation. Pelvic examination shows clear fluid in the vagina. The cervix is 50% effaced and 3 cm dilated. After 4 hours the cervix is 80% effaced and 6 cm dilated. Pelvic examination is inconclusive for the position of the fetal head. The fetal heart rate is reassuring. Which of the following is the most appropriate next step?

Perform external cephalic version

Perform Mauriceau-Smellie-Veit maneuver

A 22-year-old primigravid woman at 41 weeks' gestation is admitted to the hospital in active labor. Pregnancy has been uncomplicated. She has asthma treated with theophylline and inhaled corticosteroids. She has had 2 surgeries in the past to repair multiple lower limb and pelvis fractures that were the result of a car accident. She is otherwise healthy. Her temperature is 37.2°C (99°F) and blood pressure is 108/70 mm Hg. Examination shows the cervix is 100% effaced and 10 cm dilated; the vertex is at -4 station, with the occiput in the anterior position. Uterine activity is measured at 275 MVUs. Maternal pushing occurs during the contractions. Fetal heart tracing is 166/min and reactive with no decelerations. Epidural anesthesia is initiated for pain relief. After 4 hours of pushing, the vertex is found to be at -4 station, with increasing strength and rate of uterine contractions; fetal heart tracing shows late decelerations. Which of the following is the most likely cause of this patient's prolonged labor?

Insufficient uterine contraction

A 24-year-old primigravida at 28 weeks gestation presents to the office stating that she “can’t feel her baby kicking anymore.” She also noticed mild-to-moderate vaginal bleeding. A prenatal visit a few days ago confirmed the fetal cardiac activity by Doppler. The medical history is significant for GERD, hypertension, and SLE. The temperature is 36.78°C (98.2°F), the blood pressure is 125/80 mm Hg, the pulse is 70/min, and the respiratory rate is 14/min. Which of the following is the next best step in evaluation?

Confirmation of cardiac activity by Doppler

Order platelet count, fibrinogen, PT and PTT levels

Pain management in labor for USMLE Step 1: High-Yield OB/GYN Lessons

Pain Relief Roadmap - Setting the Stage

Goal: Balance maternal comfort with fetal/maternal safety and labor progress. Choice is guided by maternal preference, contraindications, and labor stage.
Two primary pathways exist for managing labor pain:

Labor Analgesia: Pharmacologic and Non-Pharmacologic Methods

Non-Pharmacologic: Often first-line.
- Techniques: Breathing, hydrotherapy, massage, position changes.
- Benefits: Minimal side effects, increased maternal sense of control.
Pharmacologic: For moderate-to-severe pain.
- Routes: Systemic (IV) or neuraxial (spinal/epidural).

Natural Comfort - The Drug-Free Zone

Psychoprophylaxis (e.g., Lamaze): Utilizes controlled breathing, relaxation, and a support person (doula) to manage contractions. Aims to break the fear-tension-pain cycle.
Hydrotherapy: Warm water immersion in a tub or shower can decrease anxiety and perception of pain.
Movement & Positioning: Encouraging walking, swaying, or using a birthing ball helps manage discomfort and can facilitate fetal descent.
Other Modalities:
- Massage & Counterpressure: Particularly effective for back labor caused by fetal position.
- TENS: Transcutaneous electrical nerve stimulation; non-invasive with variable efficacy.

Labor Positions for Pain Management

Systemic Soothers - Taking the Edge Off

Feature	Systemic Opioids (e.g., Fentanyl, Remifentanil)	Nitrous Oxide (N₂O)
Mechanism	µ-opioid receptor agonist	NMDA receptor antagonist
Admin	IV/IM by staff	Self-administered via mask (50% N₂O/50% O₂)
Maternal SE	Sedation, nausea/vomiting, pruritus	Dizziness, nausea, lightheadedness
Fetal Effects	↓ FHR variability, potential for neonatal respiratory depression	Minimal; rapidly cleared from neonatal circulation
Key Point	Crosses placenta; risk of neonatal sedation	Patient-controlled, rapid onset/offset

Neuraxial Blockade - The Gold Standard

Provides superior pain relief compared to parenteral opioids. Choice depends on the stage of labor and clinical scenario.

Epidural Anesthesia Needle Placement in Lumbar Spine

Feature	Epidural Anesthesia	Spinal Anesthesia
Site	Epidural space (L2-L5)	Subarachnoid space (L2-L5)
Onset	Slower (10-20 min)	Rapid (2-5 min)
Agents	Bupivacaine, Ropivacaine + Fentanyl	Bupivacaine (hyperbaric) + Fentanyl
Use Case	Labor analgesia (continuous infusion)	Cesarean delivery (single shot)
Key Risk	Accidental dural puncture	Post-dural puncture headache (PDPH)

-   **Hypotension:** Most common side effect due to sympathetic blockade.
-   **Pruritus:** Common with opioids (Fentanyl); treat with naloxone or diphenhydramine.
-   **Inadequate block:** May require catheter replacement.

⭐ PDPH presents as a postural headache (worse when upright, better when supine) 1-3 days post-procedure. Treatment of choice is an epidural blood patch.

High‑Yield Points - ⚡ Biggest Takeaways

Epidural analgesia is the most effective pain relief but risks maternal hypotension and a prolonged second stage of labor.

Spinal anesthesia provides rapid, dense blockade for cesarean delivery but carries a risk of post-dural puncture headache.

A pudendal nerve block is ideal for perineal pain during the second stage but does not relieve uterine contraction pain.

IV opioids are a systemic option but pose a significant risk of neonatal respiratory depression.

General anesthesia is reserved for emergent C-sections when regional methods are contraindicated.

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