Instrumental Delivery (Forceps and Ventouse)
Summary
Instrumental Delivery (also called Assisted Vaginal Delivery or Operative Vaginal Delivery) refers to the use of Forceps or Ventouse (Vacuum extractor) to assist with the second stage of labour when vaginal delivery cannot be safely achieved by maternal effort alone. Instrumental delivery is performed in approximately 10-15% of vaginal births in the UK. Key indications include prolonged second stage, maternal exhaustion, fetal distress (Non-reassuring CTG), and maternal conditions contraindicating prolonged pushing (e.g., Cardiac disease). Before attempting instrumental delivery, strict prerequisites must be met (Fully dilated, Head engaged, Known position, Ruptured membranes, Adequate analgesia, Empty bladder, Consent). The choice between Forceps and Ventouse depends on clinical circumstances, operator skill, and maternal preference. Forceps are more likely to achieve delivery but carry higher maternal morbidity (Perineal trauma); Ventouse has lower maternal trauma but higher failure rate and fetal scalp injuries. Complications include perineal tears (3rd/4th degree), postpartum haemorrhage, and neonatal injury (Cephalhaematoma, Subgaleal haemorrhage). [1,2,3]
Clinical Pearls
"Prerequisites Before Pulling": Fully dilated, Head engaged, Position known, Membranes ruptured, Adequate analgesia, Empty bladder, Informed consent.
"Ventouse = Less Maternal Trauma, More Neonatal Scalp Injury": Ventouse has lower rates of severe perineal tears but higher rates of cephalhaematoma and scalp lacerations.
"Forceps = More Control, More Maternal Trauma": Forceps provide better control and higher success rate but increase risk of 3rd/4th degree tears.
"Three Pulls Max": If delivery not imminent after three contractions with traction, consider abandoning and proceeding to Caesarean.
Demographics
| Factor | Notes |
|---|---|
| UK Rate | ~10-15% of vaginal deliveries are instrumental. |
| Primiparous | Much more common in first pregnancies (Longer second stage). |
| Trend | Declining slightly with increasing Caesarean rates. |
Comparison: Forceps vs Ventouse (UK Data)
| Instrument | Approximate Use |
|---|---|
| Ventouse | ~50% of instrumental deliveries. |
| Forceps | ~40-50% of instrumental deliveries. |
Fetal Indications
| Indication | Notes |
|---|---|
| Fetal Distress (Non-Reassuring CTG) | Prompt delivery required. |
| Cord Prolapse (2nd Stage) | Expedite delivery. |
| After-Coming Head (Breech) | Forceps to the after-coming head. |
Maternal Indications
| Indication | Notes |
|---|---|
| Prolonged Second Stage | >2 hours active pushing (Primip with epidural), >1 hour (Multip). |
| Maternal Exhaustion | Unable to push effectively. |
| Medical Conditions Contraindicating Valsalva | Severe cardiac disease, Severe hypertension, Cerebral pathology. |
| Premature Separation of Placenta in 2nd Stage | Need for expedited delivery. |
| Prerequisite | Notes |
|---|---|
| Head Engaged | Leading bony edge at or below ischial spines (Station 0 or below). |
| Fully Dilated Cervix | 10cm. |
| Ruptured Membranes | Amniotomy if not already ruptured. |
| Vertex Presentation | (Or after-coming head in breech). |
| Position of Head Known | Must know OA, OT, or OP position. Confirm by VE or USS. |
| Empty Bladder | Catheterize (Prevents bladder injury, Allows descent). |
| Adequate Analgesia | Epidural, Spinal, or Pudendal block. |
| Informed Consent | Written if time allows. |
| Senior Obstetrician Available | For complex/rotational deliveries. |
| Paediatrician Present | For neonatal resuscitation if needed. |
| Theatre Ready | In case of failure → Emergency Caesarean. |
By Station (Head Position)
| Type | Station | Notes |
|---|---|---|
| Outlet | Scalp visible, Leading point at +2 or below | Least difficult. Low complication rate. |
| Low Cavity | Leading point at +1 to +2 | Common. Acceptable. |
| Mid Cavity | Leading point at 0 to +1 | More difficult. Higher complication rate. Senior operator. |
| High Cavity | Head above ischial spines | CONTRAINDICATED. Proceed to Caesarean. |
By Rotation Required
| Type | Rotation |
|---|---|
| Non-Rotational | Head already OA (No rotation needed). Easiest. |
| Rotational | Head OT or OP. Requires rotation to OA. Higher risk. Senior operator only. Kielland's forceps or Rotational ventouse. |
Forceps
| Type | Description | Use |
|---|---|---|
| Non-Rotational Forceps | ||
| Neville Barnes / Simpson's | Curved blades. For OA position. Outlet/Low cavity. | Most common. |
| Wrigley's | Short, Light forceps. | Lifting out head at Caesarean. Outlet at vaginal delivery. |
| Rotational Forceps | ||
| Kielland's | Minimal pelvic curve. Sliding lock. | Rotational delivery (OT → OA). Mid-cavity. Senior operator only. |
Ventouse (Vacuum Extractor)
| Type | Description | Use |
|---|---|---|
| Kiwi (Hand-held) | Single-use, Pump integrated. | Widely used. |
| Silastic Cup | Soft cup. | Lower scalp trauma. Lower failure rate concerns. |
| Metal Cup (Bird's/Malmström) | Rigid. More traction. | Rarely used now. May still be used for OP position. |
Forceps vs Ventouse: Comparison
| Factor | Forceps | Ventouse |
|---|---|---|
| Success Rate | Higher. More control. | Lower. May detach. |
| Maternal Perineal Trauma | Higher (3rd/4th degree tears). | Lower. |
| Episiotomy | Often needed. | Less often. |
| Neonatal Scalp Injury | Lower. | Higher (Cephalhaematoma, Chignon, Subgaleal haemorrhage). |
| Rotation Capability | Kielland's – Excellent. | Can rotate, But less predictable. |
| Analgesia Required | More (Usually regional). | May use pudendal block. |
Pre-Procedure
- Confirm Prerequisites: All met.
- Explain and Consent: Risks, Benefits, Alternatives.
- Position: Lithotomy position.
- Catheterize: Empty bladder.
- Assess Position: Vaginal examination. Confirm vertex, Position (Fontanelles, Sutures). Consider USS if uncertain.
- Analgesia: Adequate (Epidural top-up, Spinal, Pudendal block).
- Theatre Readiness: For emergency Caesarean if fails.
- Assemble Team: Obstetrician, Midwife, Anaesthetist (If in theatre), Paediatrician.
Forceps Procedure (Overview)
- Check Forceps: Assemble blades, Check lock.
- Insert Left Blade First: Guide with fingers, Along sidewall of pelvis.
- Insert Right Blade: Mirror image.
- Lock Blades: Handles should lock easily if positioned correctly on sagittal suture.
- Check Application: Sagittal suture equidistant between blades. Posterior fontanelle 1-2cm above shank.
- Apply Traction: With contraction. Downwards initially, Then upwards as head crowns.
- Episiotomy: If needed (Usually mediolateral).
- Deliver Head Slowly: Controlled.
- Remove Blades: After head delivered.
- Complete Delivery: Shoulders and body.
Ventouse Procedure (Overview)
- Identify Flexion Point: 3cm in front of posterior fontanelle.
- Apply Cup: Over flexion point.
- Create Vacuum: Stepwise or direct.
- Check for Maternal Tissue Entrapment: Sweep around cup edge.
- Apply Traction: With contraction. Perpendicular to cup, Following pelvic axis.
- "Pop-Off" Limit: If cup detaches 3 times, Abandon ventouse. Consider forceps or Caesarean.
- Deliver Head: Controlled.
Maternal Complications
| Complication | Notes |
|---|---|
| Perineal Tears (3rd/4th Degree - OASIS) | Higher with forceps (9-13%) than ventouse (~5%). Risk increased with OP position, Large baby. |
| Postpartum Haemorrhage | Trauma, Uterine atony. |
| Cervical/Vaginal Lacerations | Check after delivery. |
| Urinary Retention / Bladder Injury | Catheterize. |
| Pain / Bruising | Common. Usually resolves. |
| Psychological Trauma | Debrief. Birth trauma support. |
Fetal/Neonatal Complications
| Complication | Notes |
|---|---|
| Cephalhaematoma | Subperiosteal bleed. More common with ventouse. Resolves over weeks. |
| Chignon | Scalp oedema under the cup. Resolves in 24-48h. |
| Subgaleal Haemorrhage | DANGEROUS. Bleeding under aponeurosis. Can cause hypovolaemic shock. Monitor head circumference. More common with ventouse. |
| Scalp Lacerations | Especially with ventouse. |
| Facial Nerve Palsy | Rare. Forceps pressure. Usually transient. |
| Intracranial Haemorrhage | Rare. More common with failed/traumatic delivery. |
| Jaundice | From cephalhaematoma (Haem breakdown). |
| Bruising | Especially with forceps. |
| Definition | Notes |
|---|---|
| Failure | Delivery not achieved with chosen instrument. |
| Options | 1. Switch instrument (Ventouse → Forceps). 2. Proceed to Caesarean. |
| Sequential Instruments | Expert guidance. Increased neonatal morbidity. Avoid if possible. |
| Decision | Senior obstetrician. If not confident → Abandon early. |
Key Guidelines
| Guideline | Organisation | Key Recommendations |
|---|---|---|
| Operative Vaginal Delivery | RCOG GTG 26 (2020) | Prerequisites, Classification by station, Consent, Training. |
| Intrapartum Care | NICE NG235 | Indications, Maternal choice, Perineal protection. |
Evidence Points
- Cochrane Review: No clear evidence one instrument is superior. Choice depends on clinical situation and operator skill.
- OASI Care Bundle: Reducing 3rd/4th degree tears with manual perineal protection, Episiotomy when indicated.
What is an Instrumental Delivery?
Sometimes during labour, your baby needs a little help to be born. We can use special instruments – either Forceps (Metal tongs that fit around baby's head) or a Ventouse (A suction cup on baby's scalp) – to gently guide baby out while you push.
Why might I need this?
- Your baby isn't tolerating labour well and needs to come out quickly.
- You've been pushing for a long time and are exhausted.
- Baby is in a tricky position.
- A medical condition means long pushing isn't safe for you.
Is it safe?
Both forceps and ventouse have been used safely for many years. There are some risks:
- For you: Tears to the tissues around the vagina (We try to prevent and repair these).
- For baby: Bruising or swelling on the head (Usually minor and resolves).
Will it hurt?
We will make sure you have good pain relief – usually an epidural or a local anaesthetic injection.
What if it doesn't work?
If we try and baby doesn't come out easily, we will move to a Caesarean Section to deliver baby safely. We are always prepared for this.
Primary Sources
- Royal College of Obstetricians and Gynaecologists. Operative Vaginal Delivery (GTG 26). 2020.
- O'Mahony F, et al. Choice of instruments for assisted vaginal delivery. Cochrane Database Syst Rev. 2010;(11):CD005455. PMID: 21069686.
- National Institute for Health and Care Excellence. Intrapartum care for healthy women and babies (NG235). 2023.
Common Exam Questions
- Prerequisites: "What are the prerequisites for instrumental delivery?"
- Answer: Fully dilated, Head engaged, Known position, Membranes ruptured, Adequate analgesia, Empty bladder, Consent, Theatre ready.
- Forceps vs Ventouse Maternal Trauma: "Which instrument has higher rates of 3rd/4th degree tears?"
- Answer: Forceps.
- Neonatal Complication of Ventouse: "What is the dangerous neonatal complication of ventouse?"
- Answer: Subgaleal Haemorrhage (Bleeding under aponeurosis).
- Classification: "What defines a mid-cavity delivery?"
- Answer: Leading point of head at Station 0 to +1 (At or just below ischial spines).
Viva Points
- Kielland's Forceps: For rotational delivery. Senior operator. Must know station, Position.
- Pop-Off Rule: Ventouse – If cup detaches 3 times, abandon.
- Sequential Instruments: Use with caution. Increased neonatal morbidity.
- OASI Bundle: Manual perineal protection, Slow delivery, Mediolateral episiotomy when indicated.
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists.