Operative Vaginal Birth

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So today’s episode won’t be a “how to” on operative birth; that requires some years of residency and even fellowship, but we want to help you recognize what operative births are and when to use them. For more reading, check out the new ACOG PB 219.

Operative vaginal birth is when an obstetrician or other trained birthing provider uses a device such as vacuum extractor or forceps during the second stage of labor to achieve or expedite a vaginal birth for maternal or fetal indications. The two tools generally available are forceps or vacuum extractors.

Forceps 

  • Generally, metal devices with two blades that are placed around the head of the fetus to assist in birth.

  • Consist of the components of blade, shank, lock or articulating portion, and handle 

  • The blades have a toe (front) and a heel (back toward the provider), as well as a pelvic curve and cephalic curve:

OBGynKey

  • Some history on forceps:

    1. First developed by the Chamberlen family of surgeons in France as early as possibly 1634, though they kept them secret for about 150 years.

    2. They largely haven’t changed. Simpson forceps (split shanks), for example, were created in 1848, and Elliot forceps (overlapping shanks) in 1860.

    3. There are multiple types, but the majority of forceps in use today are in the Simpson or Elliot class. Some you may encounter:

      1. Simpson - Luikhart: split shank (Simpson type), pseudofenestrated blade.

      2. Luikhart - McLain: Elliot type with pseudofenestrated blade.

      3. Tucker McLain: Elliot type, no fenestration to blade.

Vacuum Extractor 

  • A suction cup that is placed on the head of the baby approximately 2-3 cm anterior from the posterior fontanelle over the flexion point to guide the head through the birth canal.

  • Some history 

    1. The first vacuum extractor was developed by James Young Simpson in 1849.

    2. Didn’t really catch on until a Swedish doc named Tage Malmstromo developed the “ventouse” or Malmstrom extractor in the 1950s.

A Kiwi vacuum extractor

Indications and Prerequisites for Operative Vaginal Birth

  1. Indications 

    1. Prolonged second stage of labor.

    2. Suspicion of immediate or potential fetal compromise.

    3. Shortening of second stage of labor for maternal benefit (ie. maternal exhaustion or maternal cardiac issues that may make it difficult for them to Valsalva for an extended amount of time).

  2. Prerequisites (“checks” before attempt).

    1. Cervix is fully dilated and membranes are ruptured.

    2. Engagement of the fetal head.

    3. Position of fetal head is known (either by exam or by ultrasound).

    4. EFW has been performed and assessment that the pelvis is adequate for vaginal birth (don’t want to pull into a shoulder!).

    5. Adequate anesthesia.

    6. Maternal bladder has been emptied.

    7. Patient has agreed after being informed of risks and benefits of procedure.

    8. Willingness to abandon the attempt, with back-up place (ie. cesarean) in case of failure to deliver.

    9. We do not recommend doing a prophylactic episiotomy anymore, but if you have to, reasonable to give prophylactic antibiotics, per the ANODE trial, and also give if there is a 3rd or 4th degree laceration.

  3. When should you NOT perform an operative vaginal birth: 

    1. If fetal head is unengaged or fetal head position is unknown.

    2. If fetus is suspected to have osteogensis imperfecta or other both demineralization condition.

    3. If fetus is thought to have bleeding disorder (ie. thrombophilia or von Willebrand disease).

  4. Categorization of forceps deliveries (we don’t do high forceps anymore… YIKES!) 

    1. Midforceps 

      1. Station is above +2 cm, but head is engaged.

    2. Low forceps 

      1. Leading point of the fetal skull is at station +2 cm or more and not on the pelvic floor.

      2. Without rotation: rotation is 45 degrees or less (ROA, ROP, LOA, LOP).

      3. With rotation: Rotation is > 45 degrees, requires rotation with rotational forceps or Scanzoni maneuver.

    3. Outlet forceps

      1. Fetal scalp is visible at the introitus without separating the labia.

      2. Fetal skull has reached the pelvic floor.

      3. Fetal head is at or on perineum.

      4. Sagittal suture is in an AP diameter or ROA, ROP, LOA, LOP.

      5. Rotation does not exceed 45 degrees.

Counseling a Patient on Operative Vaginal Birth

  • Benefits 

    1. Avoidance of cesarean delivery for the indications above.

    2. Operative vaginal delivery is undeniably faster to achieve delivery, and when indicated, helps to avoid major surgery and its recovery and potential complications.

  • Maternal Complications 

    1. Higher risk of anal sphincter injury (10-20%), though it may be difficult to separate this out from other risks that are associated with operative vaginal birth like prolonged second stage, fetal size, episiotomy, etc. 

      1. One study that controlled for all these other clinical factors: forceps still associated with 6x increase in 3rd and 4th degree tears, and vacuum associated 2x increase.

      2. However, other studies do not clearly show that there is a significant difference in fecal or flatal incontinence through 1 year postpartum.

  • Fetal/Newborn Complications 

    1. Very low in general! Intracranial hemorrhage occurs 1/650-850 operative vaginal births and neurologic complication 1/220-385.

    2. Vacuum: usually due to traction on fetal scalp, ie. laceration, cephalohematoma, subgaleal or ICH.

    3. Forceps: facial lacerations, facial nerve palsy, corneal abrasion, and external ocular trauma, skull fracture, ICH.

      1. Rates of ICH are similar for forceps, vacuum, and cesarean deliveries performed during labor.

    4. Compared to those delivered by cesarean, those delivered by:

      1. Forceps: higher rates of fracture, facial nerve palsy, and brachial plexus injury, but lower rates of neurologic complications (ie. seizures, IVH, subdural hemorrhage),

      2. Vacuum: higher rates of cephalohematoma, fracture, and brachial plexus injury, but not central neurologic complications.

    5. Few data assess long-term consequences of operative vaginal birth on the infant, but of the studies we have, there does not appear to be significant differences in cognitive development from those born from forceps or vacuum compared to spontaneous vaginal birth.

When should you abandon operative vaginal birth? 

  1. Traditionally, it’s 3 pop-offs for the vacuum extractor, but this may depend on the type of vacuum and institutional policy.

  2. With deterioration of the fetal heart tracing without progress, or just no progress in general.

  3. Maternal request.

A Pros and Cons Comparison of Methods of Operative Vaginal Birth