Dr. Kermit Gosnell is facing five counts of murder in the deaths of a patient and four babies allegedly born alive at his street-corner clinic in West Philadelphia.
The jury deliberated for a sixth full day Wednesday without reaching a verdict.
The panel spent much of the day listening to the trial testimony of medical assistant Lynda Williams, who has pleaded guilty to two counts of third-degree murder.
Williams testified that she "snipped" a baby with scissors after it was born and helped sedate a 41-year-old patient who died of an overdose.
Gosnell's lawyer has argued that no babies were born alive during the abortions.