Espresso: Shoulder Dystocia

What is shoulder dystocia?

• After the delivery of the fetal head, the fetal anterior shoulder gets caught on the maternal pubic symphysis.

• Less common: posterior shoulder is impacted by the maternal sacral promontory 

• Reported incidence: ranges from 0.2-3% of vaginal deliveries

• Most often recognized when after delivery of the head, there is not easy delivery of the shoulders with gentle traction on the head. Can often see a “turtle” sign, when there is retraction of the fetal head from the maternal perineum 

• Risk factors 

  • Fetal macrosomia - and anything else that can cause it

    • Think maternal diabetes - Type I, Type II, or GDM, especially if poorly controlled 

  • History of shoulder dystocia (recurrence rate is 10%) 

  • Unfortunately, nothing has been reliably found to predict shoulder dystocia, including history, presence of diabetes, or even EFW or abdominal circumference to BPD ratio 

Why do we care about shoulder dystocia? 

• Risks to mom

  • Increased risk of postpartum hemorrhage (11%) 

  • Increased risk of 4th degree laceration (3.8%) 

  • Also performance of certain “heroic measures,” ie. Zavanelli and symphysiotomy (ouch) have significant risk for mom (ureteral injury, uterine rupture, cervical laceration, bladder injury)  

    • Thankfully they are rare !

    • I have never seen it in real life, but there is an … interesting episode with eclampsia, forceps, and shoulder dystocia all in one with Zavanelli’s maneuver on an episode of ER (Love’s Labor Lost, Season 1 Episode 19) from 1995.

• Risks to baby 

  • Most shoulder dystocias resolve without injury to the baby, but there is a higher overall neonatal injury rate, about 5.2% from a recent multicenter study in 2018 

  • Increased risk of brachial plexus injury from hyperextension of neck one way or the other → Erb palsy, Klumpke palsy 

  • Increased risk of clavicular or humeral fracture 

  • More rare is hypoxic-ischemic encephalopathy (HIE) 

  • Interestingly, the length of shoulder dystocia itself is not an accurate predictor of neonatal asphyxia or death 

How do we manage shoulder dystocia? 

• Prevention of shoulder dystocia 

  • Again, we cannot accurately predict shoulder dystocia, so unfortunately… it’s not easy to figure out what to do to prevent.

  • There have not been big trials looking at this time, but according to some studies looking at the cost analysis, there is some suggestion that offering primary cesarean for fetuses >5000g in non-diabetic mothers and >4500g in diabetic mothers may be “worth it.”

  • Similarly, you can consider for patients with history of shoulder dystocia where recurrence risk is ~10%.

  • What about induction of labor? 

    • Basically, there have been a lot of studies, but currently, evidence is unclear if there is benefit for earlier induction of labor vs. expectant management alone for shoulder dystocia prevention.

Maneuvers for shoulder dystocia/how to manage a shoulder dystocia

• Every hospital is going to be different, but this is how we were trained!

  1. Recognize a shoulder: turtling, shoulder not delivery easily despite gentle downward traction on the head 

  2. Communication: let the room know that there is a shoulder dystocia, ie. “We have a shoulder dystocia” - usually this will kick off a series of events 

     • The nurse may call for help, at our current hospital, there is an “emergency lever” that is pulled and help will come  

     • Talk to mom and ask her to stop pushing: “Ms. X, baby’s shoulder is stuck behind the pubic bone. I’m going to ask you to stop pushing while we help baby get out.”   

     • Once you call a shoulder dystocia, usually institutional implementation of someone to be recorder - call time, document maneuvers tried 

  3. Positioning: have nursing/other providers move mom down on the bed so that the perineum is right at the edge of the bed. Then place mom in McRobert’s maneuver, where the hips are flexed back, opening the pelvis.

  4. Maneuvers: there are no randomized controlled trials for what is better, but there are some logical steps to take that are easy to employ (McRobert’s, suprapubic pressure, and posterior arm will relieve 95% of shoulder dystocias in 4 minutes or less) 

     • Suprapubic pressure: another provider places pressure suprapubically to push the impacted shoulder under the pubic symphysis. This needs to be done in the correct direction. Often, we take a moment to figure out which shoulder is impacted and which direction it should go. Then direct the other provider by indicated with your hand or finger (“I want suprapubic pressure in this direction”) instead of verbally, because that can get confusing (ie. which right?) 

     • Posterior arm: some recent studies have shown that delivery of the posterior shoulder leads to a high success rate. This involves placing a hand into the vagina, finding the posterior arm and delivering it first. Sometimes, this may be more difficult, as it involves identifying the arm and hand, flexing it at the elbow, and gently pulling the arm around the head. If there is little room, may also require an episiotomy. 

       • Posterior shoulder sling - thread a catheter under the posterior armpit and deliver posterior shoulder this way 

     • Rubin and Woodscrew Maneuvers: Rubin’s involves placing a hand into the vagina and rotating the posterior shoulder anterior toward the fetal head. Woodscrew involves placing the hand on the anterior surface of the posterior fetal clavicle to turn the posterior shoulder until the anterior shoulder emerges.

     • Gaskin Maneuver: have the woman get on all fours and place pressure on the posterior pressure downward or upward traction on anterior shoulder.

***If these don’t work, try again. A study of 231 cases showed no association between maneuvers and neonatal injury. Try what works !

More aggressive maneuvers

• Zavanelli’s - when everything else has been tried, if the only other option is abdominal rescue for catastrophic cases, place pressure on the head to go back up through the vaginal canal for cesarean delivery 

• Symphysiotomy - cutting the symphysis. Not really a modern option in the era of readily available cesarean delivery, but has been performed in lower resourced settings.

• Breaking fetal clavicle - may decrease AP diameter, but may be difficult to perform. Always break in a manner that is away from the fetal chest (ie. pull clavicle away from body) to avoid damaging underlying structures.

Simulation is key to success in managing shoulder dystocia as a team! - if you don’t have this already, please ask about SIMing a shoulder dystocia at your institution.

• Not only to make providers more comfortable, but studies have also shown that team training protocols and sim have been associated with reduction in transient brachial plexus injury.

• Increased evidence-based management of shoulder dystocia.