In a normal vaginal delivery with the fetal head already in the vagina but not delivering, should obstetric forceps or a vacuum extractor be used?

Operative Vaginal Delivery: Forceps vs Ventouse

Both forceps and ventouse (vacuum extractor) are acceptable options when the fetal head is palpable in the vagina during normal delivery, but forceps have lower failure rates and are preferred when expedited delivery is needed. 1, 2

Primary Recommendation

The American College of Obstetricians and Gynecologists states that both forceps and ventouse are acceptable instruments for operative vaginal delivery when the fetal head is visible/palpable in the vagina, with the choice depending on operator experience and clinical circumstances. 1

Key Decision Points:

Forceps advantages:

• Lower failure rates compared to vacuum extraction 1, 2, 3
• More controlled traction and faster application 1
• More successful at achieving operative vaginal delivery 3

Ventouse (vacuum) advantages:

• Gentler on maternal tissues 1
• Lower risk of maternal pelvic floor trauma 4
• Less third- and fourth-degree perineal tears 3

Clinical Algorithm

When the fetal head is in the vagina but not delivering:

1. Assess station and position - If the head is at low station with proper positioning, either instrument is appropriate 1, 2

2. Consider urgency - If Category 2 CTG or need for expedited delivery, forceps are preferred due to lower failure rates 1, 2

3. Evaluate operator skill - Use the instrument with which you have proper training and experience 1, 5

4. Avoid cesarean section - Operative vaginal delivery minimizes maternal morbidity compared to second-stage cesarean, which carries up to 10% risk of impacted fetal head complications 1, 5

Critical Contraindications and Pitfalls

Never use a single forceps blade or ventouse as a lever to disimpact the head - this is considered dangerous and explicitly not recommended. 6, 2, 5

Absolute contraindications to operative vaginal delivery:

• Cephalopelvic disproportion (CPD) 2, 5
• Marked molding, deflexion, or asynclitism without descent 2

Specific vacuum contraindications:

• The American College of Obstetricians and Gynecologists warns that vacuum use at cesarean delivery has potential to cause significant fetal injury, including intracranial and subgaleal hemorrhage 6

Maternal and Neonatal Trade-offs

Forceps carry higher risk of:

• Third- and fourth-degree perineal tears 3
• Vaginal trauma 3
• Facial nerve injury (when improperly applied) 1, 5

Ventouse carries higher risk of:

• Failed delivery requiring cesarean 3
• Cephalhaematoma (especially with metal cup) 3
• Scalp injury 3

If Operative Vaginal Delivery Fails

If the chosen instrument fails after three attempts, abandon the procedure and proceed immediately to cesarean section. 5, 7

Prepare for potential impacted fetal head management:

• Manual vaginal disimpaction (vaginal push method) 2
• Reverse breech extraction 2
• Uterine tocolysis to relax the uterus 1

Training Requirements

High-fidelity simulation training is essential for both instruments, as proper application technique is critical to minimize complications. 6, 5