Normal Vaginal Delivery: A Complete Clinical Guide

1. Onset of Labor

• Lightening - fetal head descends into the pelvis, fundal height decreases; may occur acutely or over several weeks with increased pelvic pressure
• Bloody show - blood-tinged mucous discharge as cervical effacement begins; most women go into true labor within 3 days
• False labor (Braxton Hicks) - irregular short contractions; do not cause significant cervical dilation but may aid in cervical effacement

2. Stages of Labor

3. First Stage of Labor

Latent Phase

• Variable length: <20 hours in nulliparas, <14 hours in multiparas
• Little visible cervical dilation, but major cervical preparation occurs: softening (collagen/connective tissue changes), effacement, and anterior positioning
• Best managed at home with clear liquids
• Instructions to come to hospital: vaginal bleeding like a period, ruptured membranes, painful contractions ≥3-4 min apart, decreased fetal movement
• Prolonged latent phase can be treated with morphine - often accelerates transition to active phase

Active Phase

• Begins at ~4-5 cm dilation - this is the segment of rapid dilation
• Minimum dilation rates:
  • Nulliparous: ≥1.2 cm/hr
  • Multiparous: ≥1.5 cm/hr
• Progress depends on: strength/frequency of contractions; size, position, attitude of fetal head; bony pelvis dimensions

Fetal Monitoring in Active Phase

• Either continuous electronic fetal monitoring (EFM) or intermittent auscultation are acceptable in low-risk labors
• Low-risk: auscultate after contractions, every 30 minutes; increase to every 15 minutes in higher-risk labors
• FHR decelerations → prompt more frequent auscultation or continuous EFM

Labor Progress Curves

4. Cardinal Movements of Labor (Mechanism of Delivery)

1. Engagement - biparietal diameter passes below the pelvic inlet; presenting part at or below ischial spines (station 0)
2. Flexion - chin flexes onto chest, reducing the presenting diameter (suboccipitobregmatic) for easier passage
3. Descent - progressive downward movement through the birth canal
4. Internal rotation - occiput rotates from transverse to anterior (OA), aligning with the AP diameter of the pelvic outlet
5. Extension - as the head reaches the introitus, it extends under the pubic symphysis; the head is delivered by extension
6. External rotation (restitution) - after head delivery, the occiput rotates back to face the maternal thigh, reflecting the shoulders aligning in the AP diameter

5. Second Stage of Labor

• Begins at full cervical dilation (10 cm) - patient experiences urge to push
• Average duration: 20 minutes (multiparas) / 50 minutes (nulliparas)
• Alert for CPD if pushing exceeds 2 hours without epidural or 3 hours with epidural in nulliparas - but can continue if FHR is reassuring and descent is progressing
• Fetal heart auscultation every 15 minutes in low-risk, every 10 minutes in higher-risk

Delivery Technique

• Support the perineum with a sterile towel (posterior hand) and control the fetal head (anterior hand)
• Ask the mother to breathe through contractions (not bear down) to allow slow, controlled expulsion and reduce perineal lacerations
• Head delivers with extension
• After head delivery: suction mouth, pharynx, then nose (if meconium - use DeLee trap via wall suction; do not stimulate breathing until laryngoscopy confirms no meconium below the cords)
• Check for nuchal cord - reduce over the head if possible; if too tight, clamp and cut

• Anterior shoulder: gentle downward traction + maternal expulsive effort; hyperflexion of maternal hips helps
• Posterior shoulder: gentle upward traction; instruct mother to push gently (excessive effort causes perineal lacerations)
• Remainder of body delivers easily after shoulders

• Place baby on mother's abdomen on warm towels
• Delay cord clamping: at least 1-3 minutes after birth (increases neonatal iron stores)
• Double-clamp cord 3 cm from umbilicus and cut; obtain cord blood/pH if desired

6. Episiotomy

• Not routine - reserved for: fetal distress requiring expedited delivery, shoulder dystocia, or operative delivery (forceps/vacuum)
• Types:
  • Median (midline): easier, less discomfort during recovery, but higher risk of 3rd/4th degree extension
  • Mediolateral (45° from midline): lower risk of sphincter/rectal injury, but more painful recovery
• Technique: inject 5-10 mL of 1% lidocaine into posterior fourchette → 2-3 cm scissors incision while protecting fetal head
• Repair episiotomy and lacerations after placenta delivery

• 1st degree: skin only
• 2nd degree: skin + perineal muscle
• 3rd degree: involves anal sphincter
• 4th degree: through rectal mucosa

7. Third Stage of Labor (Placental Delivery)

• Placenta usually delivers 10-30 minutes after infant
• Signs of placental separation:
  • Lengthening of the umbilical cord
  • Sudden gush of blood
  • Change in fundal contour (uterus becomes globular and rises)
• Management:
  • Allow spontaneous separation - do NOT apply aggressive cord traction (risk: uterine inversion, cord avulsion)
  • Gentle cord traction once separation signs appear
  • Uterine massage + immediate breastfeeding promote uterine contraction
  • Oxytocin (10-40 units in 1 L NS at 250 mL/hr, or 10 units IM) after delivery to prevent atony

8. Fourth Stage (First Hour Postpartum)

• Excessive vaginal bleeding
• Boggy, enlarging fundus
• Hypotension

• Uterine massage: most often sufficient to contract the fundus and stop bleeding
• Bimanual massage alongside uterotonics for persistent atony
• Estimated normal blood loss in vaginal delivery: <500 mL

9. Neonatal Assessment - Apgar Score

• Score 7-10: normal
• Score <7: needs intervention (positive-pressure ventilation if HR <100 or apneic after 30 seconds)

10. Initial Maternal Admission Assessment

• If vaginal bleeding present: bedside ultrasound first to rule out placenta previa before any pelvic exam
• Sterile speculum to assess membrane status, cervical dilation, fetal station and presentation
• If membranes ruptured: no digital exam (even one exam increases infection risk; avoid lubricant as it causes false-positive nitrazine test)

11. Key Complications to Know