Shoulder dystocia: The unpredictable nightmare

July 9, 2020

This case involves induction of labor for a suspected large for gestational age (LGA) baby in a mother with a normal antepartum course.

A 21-year-old G2P1001 was admitted on July 28 at 38 weeks, 4 days’ gestation for labor induction for a suspected large for gestational age (LGA) baby. The patient’s original estimated date of deliver was August 22.

An ultrasound at 19 weeks, 6 days adjusted her date of delivery to August 7. The patient had a normal antepartum course, with normal antenatal screening, and normal glucose screening at 28 weeks’ gestation.

Two years earlier, the patient had given birth to an 8 lb, 10 oz male at term via an uncomplicated vaginal delivery with a three-degree extension.

During the current pregnancy, she was admitted at 33 weeks 0 days for possible preterm labor. Visual exam revealed a friable cervix, with Trichomonas vaginalis. The patient was observed for approximately 21 hours, during which she received a dose of subcutaneous terbutaline, which led to diminished contractions, without significant cervical change.

She was given a course of steroids and discharged on clindamycin and metronidazole.

On admission for labor induction on July 28, the patient’s diagnosis was advanced cervical dilatation and LGA. The admission history and physical documented a vertex presentation, with a cervix 3-cm dilated, 50% effaced, and a -2 station. The woman’s pelvis was described as “adequate.”

Documentation did not include an estimated fetal weight (EFW). Induction proceeded with intravaginal prostaglandins, inserted at 7:30 am, with regular contractions beginning approximately 40 minutes thereafter. Fetal heart tones (FHTs) revealed a Type 1 pattern, with a baseline fetal heart rate (FHR) in the 140s. Augmentation of the patient’s labor with oxytocin was begun, at 2 mU/min.

Approximately 4 ½ hours later, at 12:05 p.m., the physician examined the patient. At that time, with oxytocin at 10 mU/min, her contractions were every 1 to 2 minutes, 60- to 70-mmHg in strength, with a continued Type 1 pattern. Her cervix was 4-cm dilated, 50% effaced, at a -2-3 station, with an occiput posterior position. Amniotomy revealed a small amount of clear fluid, and an internal FHR electrode was placed.

An epidural was placed shortly thereafter. At 1:55 pm, with oxytocin at 12 mU/min, the patient’s cervix was 7- to 8-cm dilated, 90% effaced, at a 0+1 station. FHTs were in the 140s and, despite minimal variability, no decelerations were observed. At 3:45 pm, examination revealed a cervix with an anterior lip.

No mention was made of the fetal station. The patient began pushing at 4:45 pm. FHTs were stable. The physician remained in the room while the patient pushed. Severe variable decelerations to the 60s started at 5 pm and the head was delivered at 5:10 pm and spontaneously rotated from right occiput posterior to occiput anterior position. The body did not immediately deliver.

A McRoberts maneuver was used for 2 minutes and various maneuvers were performed to resolve a 6-minute shoulder dystocia. Fundal pressure was applied to assist with delivery of the body, which was accomplished at 5:18 pm. An 11 lb, 12 oz (5335 g) male was delivered with Apgar scores of 1, 6, and 8, at 1, 5, and 10 minutes, respectively. The arterial cord gases were pH = 7.19; pO2 = 23; pCO2 = 60; base excess = -7.0.

Also described was an appropriate repair of a three-degree extension.

Subsequently, placental pathology revealed focal, mild, chronic non-specific chorionitis.

The newborn examination revealed bruising of the baby’s ears, face, chest, and right underarm. The right underarm bruising was consistent with traction to the armpit. There was no movement of the left arm.

The left shoulder was noted to be “normal,” while the pediatrician could not rule out a dislocation of the right shoulder. The left shoulder would have been the anterior shoulder at time of delivery. The baby had a low blood sugar at 37 and required an infusion of dextrox 10% in water.

The baby was transferred to an academic medical center. The admission physical revealed no movement of the left upper or lower arm. Radiologic studies revealed no dislocation of the left or right shoulder.

Magnetic resonance imaging revealed avulsion of the nerve roots on the left at C8 to T1, with mild displacement of the cord to the right. There was a possible subarachnoid hemorrhage. A cranial ultrasound was normal. Computed tomography of the head revealed no evidence of intracranial hemorrhage or displacement of the midline sutures. There was swelling on the right side of the face with minor asymmetry of the coronal suture.

A neurology consult confirmed Erb’s palsy, with a significant avulsion injury and complete left brachial plexus palsy. The neurologist opined that other roots may be torn more distally. There was probable right Horner’s syndrome, right torticollis, and a hoarse voice suggestive of laryngeal paresis.

Despite intensive physical therapy, there was no recovery of the function of the left upper extremity over 5 months, associated with mild ptosis of the left eyelid and ipsilateral pupil, consistent with Bernard-Homer Syndrome.

The baby was referred to a pediatric neurosurgeon at another academic institution and underwent left brachial plexus exploration and external and internal neurolysis approximately 11 months after birth. Nerve grafting was not performed, as intraoperative electrical stimulation of the musculocutaneous nerve produced some visible and palpable contractions of the biceps brachii, and stimulation of the accessory nerve produced a similar response of the left deltoid muscle.

Six weeks after surgery, the child was able to partially extend the elbow and flex his fingers. However, there was no flexion at the elbow or extension of the fingers. Neurosurgery follow-up 4 months later (5 months postoperatively) identified no further recovery. The child continues with physical therapy.

Following discovery, the defense elected to proceed with trial, as the case was deemed highly defensible.

At trial, the plaintiff’s experts noted that induction of labor for a LGA baby is not recommended by the American College of Obstetricians and Gynecologists (ACOG). Lack of an estimated fetal weight, either clinically or with ultrasound, was a breach of the standard of care. Had the physician estimated the weight as at least 5000 g, a primary cesarean delivery should have been pursued.

Even with an estimated fetal weight > 4500 g, the risk of shoulder dystocia is up to 50%. The baby suffered permanent irreversible injuries that will require long-term physical and occupational therapy. The child will never have a normal life.

The defense experts testified that shoulder dystocia cannot be accurately predicted or prevented. None of the risk factors for macrosomia were present in this case, including preexisting diabetes and gestational diabetes, maternal obesity, excessive gestational weight gain, or abnormal antepartum glucose screening.

The patient’s first baby weighed 8 lb, 10 oz or 3934 g and was delivered vaginal without difficulty. There was no clinical evidence of macrosomia, noting that the fundal height at 38 weeks was 39 cm.

Although an estimated fetal weight was not documented, the obstetrician deemed that the mother’s pelvis was adequate, evidence that there was consideration of the estimated fetal weight.

Clinical and ultrasound estimates of fetal weight are poor indicators of actual fetal weight. Ultrasound is, at best, accurate to within 10% in estimating weight, and worse with larger babies.

Induction of labor is controversial. Earlier studies show an increased cesarean rate without a significant reduction in shoulder dystocia. Recent studies show induction of labor results in a four times reduction in the rate of shoulder dystocia.

Regardless, even a primary cesarean delivery does not eliminate the risk of birth trauma and neonatal brachial plexus injury associated with macrosomia.

Further, most macrosomic babies do not experience shoulder dystocia. Finally, brachial plexus injuries can occur as a result of intrauterine positioning, not just a result of a shoulder dystocia.

The patient rapidly entered active labor following induction. She did not experience a prolonged labor, a prolonged second stage, nor was operative delivery required. Once the shoulder dystocia was encountered, all maneuvers were appropriate. The shoulder dystocia lasted 6 minutes, which is not an extended time.

The umbilical cord gases were normal, evidence that the baby did not suffer any hypoxic compromise. The clinician’s contemporaneous documentation was excellent.

During rebuttal, the plaintiff’s experts again criticized the care, particularly the lack of documentation of an estimated fetal weight. If the estimated fetal weight had been less than 5000 g, attempting a vaginal delivery could have been justified.

However, had the estimated fetal weight been 5000 g or greater, according to ACOG, a primary cesarean delivery should have been performed. The baby weighed 5335 g and thus, a cesarean delivery should have been performed.

Further, in managing the shoulder dystocia, the documentation states, “the slightest amount of downward traction” was applied. Avulsion of the nerves does not occur without the application of excessive, improperly directed force. Avulsion injuries are not a result of intrauterine positioning.

The baby has permanent injuries with paralysis of the left arm and distortion of his face, which will result in lack of social acceptance in the future.

Defense experts testified that ACOG only states that a scheduled cesarean delivery may be beneficial and does not mandate that it be performed. The ACOG recommendations are based on expert opinion, not randomized trials.

During the reparative surgery, there was evidence of some nerve conduction, thus the current disabilities may still respond to therapy in the future.

After 6 hours of deliberation, the jury found for the plaintiff, awarding $3.5 million.

Case analysis

This case was defensible, except for two major issues: the lack of a pre-induction estimated fetal weight and the resulting nerve avulsion. The lack of an estimated fetal weight is not uncommon in shoulder dystocia cases resulting in litigation. Even though inaccurate, a clinical or ultrasound-based estimated fetal weight should be included in the initial assessment of all patients, whether for induction or in labor. Documentation of an estimated fetal weight, even if inaccurate, renders cases more defensible.

Lack of such documentation, as in this case, is a major obstacle to successful defense. Avulsion of the nerve roots on the left at C8 to T1 was an additional impediment to successful defense. Plaintiff attorneys who frequently litigate shoulder dystocia cases often pursue only cases with nerve avulsion, as the forces required to cause avulsion have been shown to exceed the forces associated with the typical maneuvers used to manage shoulder dystocia.

Further, avulsion injuries rarely recover spontaneously and require early surgical intervention, which if not successful, result in permanent disabilities. Finally, the presence of the child in the courtroom throughout the trial was a constant visual reminder of his life-long disabilities.

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