Instrumental Deliveries

Basics & Indications - Intervention Essentials

• Instrumental delivery: Forceps or vacuum to assist vaginal birth.
• Prerequisites:
  • Full cervical dilatation (10 cm)
  • Ruptured membranes
  • Engaged fetal head (Station ≥0)
  • Cephalic presentation
  • Adequate pelvis, empty bladder
  • Informed consent, adequate analgesia
• Indications:
  • Maternal: Prolonged 2nd stage, exhaustion, medical conditions (e.g., cardiac).
  • Fetal: Non-reassuring fetal status (NRFS).

⭐ Prolonged 2nd stage: Nullipara >3h (epidural), >2h (no epidural); Multipara >2h (epidural), >1h (no epidural).

Prerequisites & Contraindications - Safety First Steps

• Prerequisites (📌 Use "FORCEPS" checklist):
  • Full cervical dilation (10 cm); Fetal well-being (FHR).
  • Operator experienced; Obstruction absent (no CPD).
  • Ruptured membranes; Ready for C-section (backup).
  • Consent (informed); Cephalic (vertex) presentation.
  • Engaged head (≥0 station, ideally +2); Empty bladder; Effective analgesia.
  • Position of fetal head known precisely.
  • Station of head confirmed; Suitable instrument & setup.
• Contraindications:
  • Absolute: Incomplete dilation, unengaged head, true CPD, non-vertex (brow/face), fetal bleeding/bone disorders, maternal refusal.
  • Vacuum-specific: Gestation <34 weeks (↑IVH risk); prior multiple scalp samples.

⭐ Trial: Abandon if no descent after 1-2 pulls, or delivery not imminent after 3 pulls / 15-20 mins (vacuum).

Instruments & Application - Toolkit Tactics

Forceps Delivery:

• Types & Key Features:
  • Outlet: Wrigley's (low pelvic curve); Simpson's (fenestrated, molded head).
  • Rotational: Kielland's (transverse arrest; sliding lock; minimal pelvic curve).
• Parts: Blades (cephalic & pelvic curves), Shank, Lock, Handles.
• Application Essentials:
  • Prerequisites: Full dilatation, ROM, engaged head, known position, empty bladder, no CPD.
  • Technique: Left blade first (maternal left). Pajot's maneuver (axis traction). Episiotomy common.

Vacuum Assisted Delivery (Ventouse):

• Types: Metal cups (e.g., Malmstrom), Soft cups (e.g., Silc, Bird).
• Application Essentials:
  • Cup Placement: "Flexion point" (3cm anterior to posterior fontanelle, over sagittal suture).
  • Pressure: Negative 0.6-0.8 kg/cm² (or ~500-600 mmHg).
  • Traction: With uterine contractions, along pelvic axis.
• ⚠️ Safe Use Limits: Max 3 pulls, 20 mins total time, 2 pop-offs.

⭐ Vacuum delivery is associated with higher rates of neonatal cephalohematoma and retinal hemorrhages, whereas forceps delivery carries a higher risk of maternal perineal trauma and fetal facial nerve palsy.

Flowchart: Instrumental Delivery Key Steps

Complications & Choice - Risk Rundown

Maternal Complications:

• Forceps: ↑ Genital tract trauma (esp. 3rd/4th° tears), PPH, urinary retention.
• Vacuum: ↓ Genital tract trauma; but ↑ risk of failed procedure.

Fetal Complications:

• Forceps: Facial nerve palsy, skull # (rare), cephalohematoma (less common).
• Vacuum: Cephalohematoma (common), scalp abrasions/lacerations, retinal hemorrhage, subgaleal hemorrhage (rare, serious).

Choice Factors: Gestational age, fetal presentation/position, maternal/fetal condition, operator skill.

High‑Yield Points - ⚡ Biggest Takeaways

• Prerequisites are key: full dilatation, ruptured membranes, engaged head, adequate pelvis, empty bladder.
• Indications: Maternal exhaustion, prolonged second stage, fetal distress.
• Forceps: Preferred for preterm & face presentation. Kielland's forceps for rotation.
• Ventouse: Apply at flexion point. Chignon is common. Risks include cephalohematoma.
• Contraindications: Unengaged head, incomplete dilatation, CPD, fetal bleeding disorders (ventouse).
• Failed instrumental delivery necessitates Cesarean section.
• Complications: Maternal PPH, tears; Fetal facial palsy (forceps), cephalohematoma (ventouse).