Second stage of labor

Second stage of labor

Second stage of labor

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Second Stage of Labor - The Final Push

  • Definition: Full cervical dilation (10 cm) to delivery of the infant.
  • Duration: Varies by parity and anesthesia.
    • Nulliparous: ~50 min (up to 3 hours with epidural).
    • Multiparous: ~20 min (up to 2 hours with epidural).
  • Cardinal Movements: Fetal descent through the pelvis.

    ⭐ Persistent occiput posterior (OP) is the most common malposition, associated with a prolonged second stage, intense back pain, and higher rates of operative delivery.

Cardinal Movements of Labor

Cardinal Movements - Baby's Grand Exit

Cardinal movements of labor

Sequential fetal movements through the maternal pelvis, crucial for successful vaginal delivery.

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    • Engagement: Biparietal diameter passes the pelvic inlet.
    • Descent: Downward passage through the pelvis.
    • Flexion: Fetal chin tucks to chest.
    • Internal Rotation: Occiput rotates towards the pubic symphysis.
    • Extension: Head extends as it passes under the pubic symphysis.
    • External Rotation (Restitution): Head realigns with the shoulders.
    • Expulsion: Delivery of shoulders and body.

⭐ Asynclitism, where the fetal head is misaligned with the maternal pelvis (sagittal suture not centered), can halt labor progress.

Management & Monitoring - Coaching the Delivery

  • Pushing Technique:
    • Encourage spontaneous, open-glottis pushing with contractions.
    • Avoid sustained, closed-glottis (Valsalva) pushing to ↓ risk of fetal acidosis & perineal trauma.
  • Maternal Positioning:
    • Upright or lateral positions (e.g., squatting, hands-and-knees) are preferred over supine.
    • Helps optimize pelvic diameters and may shorten the stage.
  • Fetal Monitoring:
    • Continuous or intermittent auscultation per ACOG guidelines.

⭐ The Ferguson reflex-pressure on the cervix and vaginal walls-triggers oxytocin release, strengthening contractions and the maternal urge to push.

Labor Arrest & Dystocia - When Things Get Stuck

  • Arrest of Descent: Defined by the American College of Obstetricians and Gynecologists (ACOG) as no fetal descent after specific durations of pushing in the second stage of labor.
  • Diagnostic Criteria (Time spent pushing with no descent):
    • Nulliparous: ≥4 hours with an epidural, ≥3 hours without.
    • Multiparous: ≥3 hours with an epidural, ≥2 hours without.

⭐ Always evaluate the "3 Ps" (Power, Passenger, Passage) to determine the etiology before intervening. This is a classic exam concept.

  • Etiology (The 3 Ps):
    • Power: Inadequate uterine contractions (use IUPC to assess).
    • Passenger: Fetal malposition (e.g., occiput posterior, asynclitism) or macrosomia.
    • Passage: Cephalopelvic disproportion (CPD).

High‑Yield Points - ⚡ Biggest Takeaways

  • Begins at full cervical dilation (10 cm) and ends with delivery of the infant.
  • Duration is longer in nulliparous women and with epidural anesthesia; prolonged if >3 hours (nulliparous) or >2 hours (multiparous) with an epidural.
  • Key cardinal movements are internal rotation to pass the ischial spines and extension of the fetal head.
  • Progress is monitored by assessing fetal station (descent relative to the ischial spines).
  • Arrest of descent is a major indication for operative vaginal delivery (forceps/vacuum) or cesarean section.

Practice Questions: Second stage of labor

Test your understanding with these related questions

A 30-year-old woman, gravida 1, para 0, at 40 weeks' gestation is admitted to the hospital in active labor. Pregnancy was complicated by iron deficiency anemia treated with iron supplements. At the beginning of the first stage of labor, there are coordinated, regular, rhythmic contractions of high intensity that occur approximately every 10 minutes. Four hours later, the cervix is 100% effaced and 10 cm dilated; the vertex is at -1 station. Over the next two hours, there is minimal change in fetal descent; vertex is still at -1 station. Fetal birth weight is estimated at the 75th percentile. The fetal heart rate is 145/min and is reactive with no decelerations. Contractions occurs approximately every 2 minutes with adequate pressure. Epidural anesthesia was not given, as the patient is coping well with pain. Which of the following is the most appropriate next step in management?

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Flashcards: Second stage of labor

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Hepatitis B can be transmitted from mother to baby during _____

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Hepatitis B can be transmitted from mother to baby during _____

delivery

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