Instrumental Delivery
Instrumental delivery, AKA operative vaginal delivery, refers to the use of suction cups or forceps to assist vaginal delivery in the second stage of labour. The procedure is carried out by an experienced obstetrician with facilities for caesarean delivery available in case instrumental delivery fails.
Classification of instrumental delivery
| Classification | Description |
|---|---|
| Mid | Fetal head at station 0 |
| Low | Leading point of the skull is at station +2 or more but not on the pelvic floor |
| Outlet | Fetal scalp is visible without separating the labia, has reached the pelvic floor or rotation does not exceed 45 degrees (in ROA or LOA position) |
- Indications for instrumental delivery
- Failure to progress in the second stage of labour
- Nulliparous women with lack of progress for 3 hours with regional anaesthesia or 2 hours without regional anaesthesia
- Multiparous women with lack of progress for 2 hours with regional anaesthesia or 1 hour without regional anaesthesia
- Maternal exhaustion +/ vomiting and distress
- Medical contraindications to bearing down e.g. cardiac disease, myasthenia gravis
- Fetal distress
- Failure to progress in the second stage of labour
Prerequisites for Instrumental Delivery (Safety Criteria)
- Abdominal exam
- Head is < 1/5 palpable on abdominal exam (commonly 0/5 palpable)
- Vaginal exam
- Cervix is fully dilated and membranes have ruptured
- Station is at the level of the ischial spines or below (0/+1/+2/+3)
- Less than moderate caput and moulding
- Adequate pelvix
- Preparation
- Clear explanation and informed consent
- Pudendal block (for mid-pelvis rotational delivery)
- Perineal block (for low-pelvic or outlet delivery)
- Empty the bladder and remove foley catheter (or deflate the balloon)
- Episiotomy (routine episiotomy is does not reduce the risk fo severe perineal tearing)
- Aseptic technique
- Prepare theatre staff in-case forceps delivery fails
- Inform paediatrics for neonatal resuscitation
- Anticipate for shoulder dystocia, perineal trauma, and post-partum hemorrhage
Vacuum (Ventouse) Delvery
Ventouse delivery is preferred as first-line delivery by maby obstetricians. It is performed by placing the suction cup on the flexion point (located on the vertex) and applying traction with uterine contractions.
- Complications of ventouse delivery
- Failure to achieve vaginal delivery
- Cephalohematoma
- Retinal hemorrhage
Forceps Delivery
Forceps consist of paired blades with shanks joined to gether at a lock, with handles that provide a point for traction. Rotational forceps e.g. Kielland forceps can be used to correct malpositioning while conventional forceps can be used for traction in occiput-anterior positions.
Complications of Instrumental Delivery
- Maternal complications of instrumental deliver
- Postpartum hemorrhage
- Episiotomy
- Perineal lacerations
- Fecal and flatus incontinence from injury ot the anal sphincter
- Bladder injury with urinary incontinence
- Injury to the femoral and obturator nerve (resolves in 6 – 8 weeks).
- Fetal complications of instrumental delivery
- Cephalohematoma from suction
- Facial nerve palsy with forceps
- Subgaleal hemorrhage
- Intraventricular hemorrhage
- Skull fracture
- Spinal cord injury
