## Facts

- Hundreds of plaintiffs filed products-liability actions alleging that prenatal exposure to Bendectin caused birth defects.
- The cases were consolidated for coordinated pretrial proceedings as multidistrict litigation in the Southern District of Ohio.
- Plaintiffs asserted claims including negligence, strict liability, breach of warranty, fraud, gross negligence, and negligence per se tied to alleged FDCA misbranding.
- Due to the number of cases and scientific complexity, the district court ordered a phased (trifurcated) trial: (1) general causation, (2) liability, and (3) damages.
- Phase I was limited to whether Bendectin is capable of causing birth defects, using a representative subset of cases and excluding individualized liability and damages evidence not bearing on general causation.
- The Phase I jury found plaintiffs failed to prove by a preponderance of the evidence that Bendectin caused birth defects.
- The district court entered judgment for the manufacturer in the cases to which the Phase I causation determination applied.

## Issues

1. Whether the district court abused its discretion under Federal Rule of Civil Procedure 42(b) by ordering a trifurcated trial and trying general causation first.
2. Whether limiting Phase I to general causation—excluding individualized injury/damages evidence and restricting “human impact” material—unfairly prejudiced plaintiffs and denied a fair trial.

## Decision

- The Sixth Circuit affirmed the judgment for the manufacturer.
- The district court did not abuse its discretion in ordering separate trials and sequencing general causation as a threshold issue.
- The evidentiary and instructional rulings that kept Phase I focused on causation and reduced prejudice or confusion were within the district court’s discretion and did not deprive plaintiffs of a fair trial.
- The jury instructions, considered as a whole, correctly stated plaintiffs’ burden of proof and did not mislead the jury.

## Legal Principles

- Federal Rule of Civil Procedure 42(b) permits separate trials of issues to further convenience, avoid prejudice, and advance expedition and economy; district courts have broad discretion in applying the rule in complex litigation.
- In mass-tort/MDL proceedings, a court may treat general causation as a distinct, threshold issue and try it before individualized liability and damages when doing so can conserve resources and clarify common questions.
- A court may exclude evidence under Rules 402 and 403 when it is irrelevant to the limited issue being tried or when its probative value is substantially outweighed by risks of unfair prejudice, confusion, or distraction from the defined scientific question.
- Trial management choices and related evidentiary rulings are reviewed for abuse of discretion, with reversal requiring prejudicial error affecting substantial rights.

## Conclusion

The Sixth Circuit held that, in large-scale products-liability MDL litigation centered on complex scientific proof, a district court may trifurcate proceedings and try general causation first, while limiting emotionally charged or individualized evidence, without denying a fair trial; because plaintiffs failed to prove general causation, judgment for the manufacturer was affirmed.


In re Bendectin Litig., 857 F.2d 290 (6th Cir. 1988)