Fetus age debated in Peterson trial

Oakland Tribune, Oct 22, 2004 by Jason Dearen, STAFF WRITER

REDWOOD CITY -- Scott Peterson's defense stumbled Thursday when a key expert witness testifying about the gestational age of the Petersons' unborn child admitted he partially based his findings on unreliable information.

The witness, Dr. Charles March, said that the earliest date Laci and Scott Peterson's unborn child could have died was Dec. 29 -- five days after the Modesto woman vanished.

But while March's conclusion supported the central contention of defense attorney Mark Geragos' case -- that the fetus was still alive days after Laci Peterson disappeared -- his combative demeanor under cross-examination and confusing calculations culminated in the exasperated witness asking the prosecution to cut him some slack.

In addition to March's testimony, Judge Alfred Deluccchi announced that he will sequester the jury while they decide Peterson's guilt or innocence. The judge stood by his estimate that the jury will get the case Nov. 3.

But legal experts watching the trial said March's performance was a setback for the defense and that Geragos has his work cut out for him before closing arguments.

March was a crucial defense witness because, in his opening statement, Geragos said that if the gestational age of the Petersons' fetus was more than 33 weeks -- the age prosecutors contend it was when it died -- then Scott Peterson could not have murdered his wife.

One of the prosecution's two experts who testified on this matter, a forensic anthropologist, could only provide a gestational age range of 32 to 40 weeks, based on measurements of the fetus' bones. Another expert, using a bone measurement and Laci Peterson's first ultrasound, estimated that the fetus died around Dec. 23, 2002, which fit the DA's time-of-death theory.

March, a fertility specialist, said determining the gestational age of a dead fetus using ultrasound is "less than a nonscience."

"It's 100 percent impossible to identify by ultrasound a specific date," he said.

March based his calculations on a home pregnancy test Laci allegedly took June 9 -- a fact contained in none of the medical records. The June 9 date was based on the statements of one of Laci's friends, who held a baby shower for Laci. The friend, Renee Tomlinson, said the pregnant woman called her in excitement after learning of the test's results.

Prosecutor Harris zeroed in. "Is it standard practice to use statements from someone at a baby shower in your studies?" Harris asked. March, shifting back and forth in his seat, said no.

Then Harris pointed out that March had listed June 9 and June 11 in his report as the dates of Laci's pregnancy tests.

March, speaking loudly, said: "I would like everyone to cut me some slack ... I'm sorry I made an error."

The doctor said he used the pregnancy test as only one factor in computing his Dec. 29 date. He said that Laci's obstetrician- gynecologist changed her due date after her second ultrasound from Feb. 10 to Feb. 16. That's important, March said, because it shows the fetus was six days younger -- which would push the prosecution's experts' findings back six more days.

But Harris reminded March that the first ultrasound -- which his experts used to make their findings -- is considered by the medical community to be the most accurate. Harris also suggested that perhaps the fetus was just small at the time of Laci's second ultrasound, which could explain why the doctor changed the due date.

March, his slicked-back hair now disheveled, jumped from his seat and began scribbling calculations on a large white pad near the jury. He attempted to show that if the baby was indeed just small at the time of Laci's second ultrasound, then its larger size at the time of death means that it lived longer than the 33 weeks prosecutors contend.

Jurors furrowed their brows as March scribbled numbers on the pad. Prosecutor Birgit Fladager, sitting in the front row of the seating gallery, buried her face in her hands, her body convulsing with laughter.

In the end, March's credibility was in question by most of the legal analysts who viewed his testimony. "There were moments today that reminded me of Chernobyl," said Stan Goldman, a criminal law professor at Loyola Law School in Los Angeles.

Former San Francisco prosecutor Jim Hammer said the fact that March used the date of the home pregnancy test provided by the recollection of a friend was the most damaging. "An opinion is only as strong as what it's based on. This comes down to a secondhand hearsay conversation," he said.

Staff writer Jason Dearen can be reached at (650) 306-2425 or by e- mail at jdearen@sanmateocountytimes.com .

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