When “Maternal Forces” Become a Litigation Theory: A Daubert Challenge in a Brachial Plexus Case

Severe brachial plexus injury cases often turn on a single, sharply contested question: what caused the nerve damage—obstetrical forces applied by the physician, or the natural forces of labor itself? In a recent Florida medical malpractice case involving a catastrophic, permanent five-root brachial plexus injury, the plaintiff challenged the admissibility of the defense’s causation theory under Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993), arguing that it lacks a reliable scientific foundation.

The Injury at Issue

The child at the center of the case, Baby Boy, was delivered at Southside Medical Hospital in northwest Florida during a shoulder dystocia—a known obstetrical emergency in which the baby’s shoulder becomes impacted behind the maternal pelvis after delivery of the head. Immediately after birth, the child exhibited no movement in the right arm.

Surgical exploration later revealed devastating injuries: ruptures and avulsions involving all five roots of the brachial plexus (C5 through T1). These are not minor stretch injuries. They are permanent, structurally destructive injuries requiring nerve grafts and transfers, with no possibility of full recovery.

The plaintiff alleges the injury was caused by excessive traction applied during delivery rather than accepted maneuvers for resolving shoulder dystocia.

The Defense Theory: “Maternal Forces”

The defense intends to present expert testimony that the injury was caused not by obstetrical traction, but by maternal expulsive forces—the natural contractions and pushing efforts that occur in every vaginal delivery.

In other words, the defense theory is that routine labor forces alone produced one of the most severe forms of brachial plexus injury known in medicine.

To support this theory, the defense relies primarily on two experts: a pediatric neurosurgeon and an obstetrician.

The Problem: No Literature, No Experience, No Methodology

During deposition, however, both experts were unable to identify any meaningful scientific support for their opinions.

They could not point to:

• Peer-reviewed studies
• Published case reports
• Clinical literature describing similar injuries caused by maternal forces alone
• Or personal clinical experience demonstrating such a mechanism

Instead, the testimony revealed a consistent limitation: the absence of any scientific or experiential foundation linking maternal forces to catastrophic, multi-root avulsion injuries of this severity.

As the plaintiff argues, this is not a gap that can be filled by speculation.

A Critical Distinction in the Medical Literature

The Plaintiff has filed a motion to exclude the medical testimony that maternal forces caused Baby Boy’s injuries. The motion emphasizes an important distinction that even the defense experts did not dispute: not all brachial plexus injuries are the same.

The medical literature does recognize that maternal forces may be associated with mild, temporary nerve injuries—neuropraxias—that often resolve without surgery and do not involve structural nerve destruction.

But the injury in this case is fundamentally different.

It involved:

• Ruptures of nerve roots
• Avulsions (nerve roots torn from the spinal cord)
• Permanent functional loss
• Surgical reconstruction attempts

As plaintiff’s expert confirmed, there are no published reports of spontaneous maternal forces causing this type of catastrophic, multi-level avulsion injury.

The Experts’ Reliance on a Single Narrative Source

When pressed on what actually supports their opinions, the defense experts ultimately converged on a single foundation: the delivery note of the defendant obstetrician.

That note—prepared after the injury was known—forms the backbone of the defense causation theory.

Both experts conceded, in substance, that if the factual account in the note is inaccurate or incomplete, their opinions fail.

Why This Matters Under Daubert

Under Daubert, expert testimony must be grounded in sufficient facts or data and derived from reliable principles and methods reliably applied to those facts.

The plaintiff’s motion argues that requirement is not met here because:

• The opinions are not supported by medical literature
• They are not grounded in clinical experience involving the phenomenon described
• They are not the product of an independent methodological analysis
• And they depend entirely on accepting one party’s factual narrative without verification

In essence, the experts did not independently determine causation—they accepted it from the record and reasoned backward.

The Core Issue for the Court

Stripped of literature, clinical experience, and independent analysis, the defense causation theory reduces to a single proposition:

ordinary maternal pushing caused a catastrophic, permanent, five-root brachial plexus injury

The plaintiff argues that this proposition is not supported by reliable scientific evidence and therefore cannot be presented to a jury under Daubert.

Conclusion

The motion asks the court to exclude the defense causation opinions attributing the injury to maternal expulsive forces, on the grounds that they are not based on sufficient facts, not grounded in reliable methodology, and not reliably applied to the evidence in the case.

In short, the plaintiff contends that expert testimony cannot substitute for science, and assumption cannot substitute for methodology.

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Jeffrey P. Gale, P.A. is a South Florida based law firm committed to the judicial system and to representing and obtaining justice for individuals – the poor, the injured, the forgotten, the voiceless, the defenseless and the damned, and to protecting the rights of such people from corporate and government oppression. We do not represent government, corporations or large business interests.

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