• Vacuum Assisted Vaginal Delivery

    Module to assist in resident knowledge for vacuum assisted vaginal deliveries


    Vacuum Assisted Vaginal Delivery

    Table of contents

    • Instrument Background
    • Indications for VAVD
    • Contraindications
    • Delivery Technique
    • Termination Criteria
    • Maternal Complications
    • Fetal Complications
    • Informed Consent
    • Documentation of Delivery

    Instrument Background

    Kiwi Omni Cup
    • Flexible Stem
    • Rigid Cup
    • Traction Gauge

    KiwiOmniCup

    MityVac
    • Rigid Stem
    • Soft Cup
    • Mushroom and Bell Cups

    mushroom&bell

    Design

    • A metal cup, while more likely to result in successful vaginal birth than a soft cup, had more cases of fetal scalp injury and cephalohematoma
    • A "mushroom" or a "cup" design offers a lower profile for non-occiput anterior application to the flexion point
    • Freely rotating stem allows minimized torque on the scalp to decrease abrasions
    • Pressure gauges limit operator from exceeding recommended force
    • Quick release valves

    Indications

    • Prolonged second stage
      • 3 hours of pushing for nulliparous women
      • 2 hours of pushing for multiparous women
      • Longer durations may be appropriate on an individual basis such as epidural anesthesia or fetal malposition as long as progress is being documented
    • Suspicion of immediate or potential fetal compromise
    • Maternal exhaustion or medical condition requiring an assisted second stage (cardiac or neurologic disease)

    Contraindications

    Absolute
    • Less than 34 weeks gestation
    • Less than 2500g estimated weight
    • Fetal demineralizing disorders (OI)
    • Fetal bleeding disorders
    • Malpresentation – face, brow, or breech
    • Unengaged vertex
    • Incomplete Cervical Dilation
    • Inability to obtain informed consent
    Relative
    • Suspected macrosomia of >4500g
    • Prior scalp pH or multiple fetal scalp electrodes
    • Inadequate analgesia

    Prerequisites for Delivery

    • Fully dilated cervix
    • Ruptured membranes
    • Engaged fetal head
    • Known fetal position
    • Estimated fetal weight
    • Pelvis assessed to be adequate for delivery
    • Adequate analgesia
    • Bladder emptied
    • Informed consent obtained
    • Ability to abdomen and do cesarean delivery in case of failure

    Delivery Technique

    Five step technique for proper placement
    • Confirm fetal station is at least +2
    • Confirm complete dilation and ruptured membranes
    • No cephalopelvic disproportion suspected
    • Review estimated fetal weight
    Delivery Pearls
    • Place cup over Flexion Point: 3cm anterior to the posterior fontanelle along the sagittal suture
    • Apply 450 - 600 mmHg pressure on the device, as fast as desired
    • Suction may remain on until delivery achieved, but a total time of <20 minutes

    Vaca Delivery Technique

    1. Locate Flexion Point & Calculate Distance
    • Flexion Point: Along Sagittal Suture 3cm forward of the Posterior Fontanelle
    • With the opposite hand, note the distance where finger meets introitus. This is the distance you will insert the cup in step 3.
    2. Hold & Insert Cup
    • Hold the cup with thumb on the tube in the groove, fingers on foam, and insert into the vagina. After inserting, adjust the cup so it lies flat against the fetal head along the midline
    • Place the groove and stem of the cup at 12 o’clock which allows one to visualize rotation as descent occurs
    3. Move Cup Over Flexion Point
    • Note 6 & 11cm markings on stem tubing. Referencing these markings to know how far to insert the cup. Push cup posteriorly along maternal midline over flexion point. Insertion distance is the distance measured in Step 1.
    • The flexion point is along the midline. Don’t push the cup laterally
    4. Create Vacuum & Exclude Maternal Tissue
    • Use palm pump to create vacuum. Once initial vacuum is created, feel around cup to exclude ay maternal tissue. Then continue pumping to 600 mmHg
    • Create vacuum to green section on gauge. If possible, burry the green so it is no longer visible.
    5. Initiate Traction
    • Initiate traction along axis of pelvis. Pull during contractions. Do not move handle up and down or side to side while pulling
    • Use thumb and index finger of non-pulling hand to support the cup and the fetal head while pulling. This will help identify loss of vacuum before a pop-off occurs, while also providing feedback on descent.
    • 2x2 fingertip grip. Ensure you have two fingers on the handle to each side of the stem. This helps with equal pulling while reducing the likelihood of accidentally pushing the vacuum release button.

    The consent discussion must include a description of the procedure, the rationale for proposing it (diagnosis), the expected benefits of operative vaginal delivery, alternative treatment methods, and the risks of the procedure. It is preferable to discuss the procedure and its risks early in labor so that all questions and concerns can be handled without the pressure of an evolving emergency.

    “Your infant is showing signs of fetal distress necessitating an expedited delivery. With this, I recommend we proceed with a vacuum assisted delivery. What this means is that I would apply a vacuum cup to the infants head and with subsequent contractions, we would assist in guiding the infants head below the pubic bone to aid in a quicker delivery. Risks of this procedure include risk of cephalohematoma, scalp or facial laceration, and jaundice to the baby and increased risk of perineal laceration, pain, and incontinence to mother. The alternative would be proceeding with an urgent cesarean delivery that also has inherent risks of bleeding, infection, and damage to surrounding structures such as the cervix, bladder, ureter, and infant.”

    Documentation

    • Indication for procedure
      • Arrest of descent, non-reassuring fetal status, maternal exhaustion, assisted second stage
      • Reaffirm no contraindications exist and review of documented EFW
    • Fetal status
      • Station, position, estimated fetal weight, fetal heart rate tracing
    • Discussion of informed consent with the patient
    • Description of the procedure
      • Bladder empty, fully dilated cervix, type of analgesia, consent for delivery and cesarean delivery, pediatrician called to be at delivery, anesthesia ready for cesarean section if necessary
      • Type of vacuum cup, adequate placement, total time of vacuum, whether vacuum was reduced between pulls, number of pulls and contractions, number of pop-offs, description of progress with each pull, episiotomy
      • Inspection of baby after delivery

    Causes of Failed Delivery

    • Non-Occiput Anterior Presentation
    • Fetal Macrosomia
      • EFW >3750g as compared to <3250g
    • Incorrect Technique
      • Pulling without maternal effort
      • Incorrect axis of force
    • Incorrect Placement
      • Paramedian or Deflexing applications
    • Large fetal caput succedaneum

    Termination Criteria

    The maximum time to safely complete a vacuum assisted delivery and number of acceptable “pop-offs” are unknown

    • 15-20 minutes of total application time
    • If the cup “pops off” 3 times
    • No descent with subsequent pulls
    Cooper Surgical
    • Never apply the cup to any portion of the infant’s face
    • Abandon vacuum-assisted delivery if the vacuum cup disengages (pops off) three times
    • Do not operate vacuum pump at tractive levels for more than ten cumulative minutes of traction or total procedure time of 15 to 30 minutes
    Clinical Innovations
    • Do not place cup on any portion of fetal face or ear. Only place cup over flexion point
    • Do not twist, torque or use excessive force
    • Do not reapply if cup has been disengaged two times

    Maternal Complications

    • Anal Sphincter Injuries
      • VAVD two-fold increase in 3rd and 4th degree lacerations
      • FAVD six-fold increase in 3rd and 4th degree lacerations
        • Rate of subsequent sphincter injury is 3.2%, but increased if subsequent operative birth is performed
    • Maternal Lacerations
      • Vaginal, Cervical, Bladder, Rectal
        • Higher rate of laceration in FAVD than VAVD
    • Maternal incontinence
    • Postpartum pain

    Neonatal Complications

    • Subgaleal hematoma
      • Cross the suture line
      • Allow large amounts of fetal blood volume to escape in the space and thus can be fatal
    • Cephalohematoma
    • Retinal hemorrhage
    • Neonatal jaundice
    • Brachial plexus injury
    • Scalp laceration
    • Facial Injury
      • Risk increased with Forceps compared to Vacuum delivery

    Mnemonic for Vacuum Extraction

    • Ask for help; address the patient (informed consent) assess anesthesia needs
    • Bladder empty
    • Cervix fully dilated
    • Determine fetal position and think of shoulder Dystocia
    • Extractor and resuscitation Equipment ready
    • Flexion point application
    • Gentle traction in the proper axis
    • Halt traction when the contraction is over; Halt procedure if it is not progressing normally
  • REFERENCES
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  • License

    Cite as: jsander. "Vacuum Assisted Vaginal Delivery." Litsignal. Atanemi, Jun 9, 2019. Web. Jun 28, 2025.