No progressive descent after 3 pulls OR 3 'pop-offs' of ventouse.
Mnemonic: FORCEPS
F: Full Dilation • O: Open Membranes • R: Ruptured Membranes • C: Cephalic • E: Engaged • P: Pelvis • S: Station
Friedman Curve (Reference)
Latent Phase: Para 0 (≤20h), Para 1+ (≤14h). Active Phase: 1.2cm/h (Para 0), 1.5cm/h (Para 1+). *Note: WHO now uses 1cm/h threshold.*
Guidelines & Evidence
Clinical Details
Section 1
When to Use
Primary Clinical Indications
Prolonged second stage of labor (lack of progress despite adequate pushing efforts)
Maternal exhaustion or failure of voluntary expulsive efforts
Medical need to shorten the second stage (e.g., severe maternal cardiac disease, severe hypertension, aneurysmal disease)
Non-reassuring fetal heart rate (FHR) pattern requiring expedited delivery when vaginal birth is imminent
Absolute Contraindications (When NOT to Use)
Do NOT attempt if: fetal head is unengaged, fetal position is unknown, cervix is not fully dilated, or in suspected fetal bleeding/demineralization disorders (e.g., hemophilia, osteogenesis imperfecta). Vacuum extraction is strictly contraindicated in preterm gestations <34 weeks due to massive intraventricular hemorrhage risk.
Section 2
Formula & Logic
Prerequisites for Procedure (ACOG Guidelines)
Cervix is 10 cm (fully) dilated and membranes are ruptured
Fetal head is engaged in the pelvis (station ≥ +2 is optimal)
Exact fetal lie, presentation, and position are known
Clinically adequate maternal pelvis
Empty maternal bladder
Adequate anesthesia in place
Operator is experienced and capable of performing an immediate cesarean section if the procedure fails
Instrument Types
Vacuum Extractor
Plastic/metal cup applied to fetal scalp via suction. Traction is applied synchronized with contractions. Lower maternal trauma risk.
Forceps Delivery
Metal articulated instruments applied to the sides of the fetal head. Allows for both traction and rotation. Higher success rate, but higher maternal trauma risk.
Section 3
Pearls/Pitfalls
Key Strengths
Can rapidly resolve non-reassuring fetal status, often faster than preparing for a cesarean section when the head is low
Avoids the severe maternal surgical morbidity and future uterine scarring associated with cesarean delivery
Known Limitations and Risks
Maternal: Markedly increased risk of severe perineal lacerations (3rd and 4th degree), anal sphincter injury, and pelvic floor dysfunction, particularly with forceps
Fetal: Risk of scalp lacerations, cephalohematoma, subgaleal hematoma, facial nerve palsy, and retinal hemorrhage
Sequential use of both instruments (failing with vacuum, then applying forceps) exponentially increases the risk of severe neonatal intracranial injury and is explicitly discouraged
Section 4
Next Steps
Successful Extraction
01
Thoroughly inspect the vaginal vault and perineum for severe lacerations or cervical tears
02
Repair anal sphincter injuries systematically via skilled operator
03
Alert pediatrics to observe the neonate for signs of subgaleal hemorrhage or pathological jaundice (due to resolving hematomas)
04
Provide aggressive maternal postpartum analgesia
Failed Attempt
01
Abandon the vaginal approach immediately if progress is not made with appropriate traction
02
Do NOT sequentially switch from vacuum to forceps (or vice versa)
03
Proceed immediately to an operative delivery (cesarean section) recognizing the high likelihood of an impacted fetal head
Section 5
Evidence Appraisal
Primary Guidelines
Practice is derived from the ACOG Practice Bulletin on Operative Vaginal Birth. The guidelines strictly enforce the abandonment of the procedure if descent does not occur, directly citing the massive increase in perinatal morbidity associated with forced, sequential instrument use.
Section 6
Literature
Historical Context
The obstetric forceps were famously invented by the Chamberlen family in the 17th century, kept as a secret family trademark for over a century. The vacuum extractor (Ventouse) was later popularized in the 1950s by Tage Malmström as an alternative attempting to reduce maternal perineal trauma.
