REDWOOD CITY – Conner Peterson probably died in the womb about Christmas Eve 2002, an expert testified this morning.
But moments before the noon recess, Dr. Greggory DeVore agreed that he might alter that conclusion if the baby’s date of conception could be proved.
Scott Peterson’s defense attorney, Mark Geragos, gave no indication of how he might establish his suggestion that the true conception date was May 16, 2002. His client is not expected to take the witness stand.
"Unless you’re there, you can never really know," DeVore said, drawing laughter from the courtroom. He and other doctors had figured the conception date at May 20, 2002.
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DeVore said he considered the date Laci Peterson gave doctors for her last menstrual period and two ultrasound tests conducted during her pregnancy. He then projected the fetus’ rate of growth, measured a thighbone taken from his remains and calculated his death date: Dec. 23, 2002.
Authorities think Scott Peterson smothered or strangled his pregnant wife that night or early the next morning and used a solo fishing trip to San Francisco Bay as cover to dump her body.
The remains of mother and son washed ashore four months later less than two miles from the spot indicated in his alibi.
DeVore appeared more than willing to contend with Geragos, who repeatedly insisted that Conner may have been slain as late as Dec. 28, based on different methods of calculating.
By that time, Scott Peterson had come under heavy surveillance and presumably would not have had the opportunity to commit murder. His defense team contends that someone else kidnapped Laci Peterson.
Geragos began the trial 17 weeks ago by telling jurors, "The evidence is going to show you that this baby was born alive." When a forensic pathologist who examined Laci Peterson’s remains testified last week that was impossible, Geragos suggested that the baby was cut from her womb from a point that must have rotted away during decomposition.
Much of Geragos’s argument centered on a prediction by Laci Peterson’s obstetrician-gynecologist that Conner would be born about Feb. 16, 2003, based on measuring his femur, or thighbone, in an ultrasound exam conducted on Sept. 24, 2002.
DeVore said it’s smarter to rely on a "crown-rump" measurement, from the tip of the fetus’ head to his buttocks, taken from a July 16, 2002 ultrasound.
Absent knowledge of actual conception, the first-trimester crown-rump measurement is considered an industry gold standard for predicting a due date, DeVore said. That’s because differences in growth rate become larger as fetuses get older, he said.
Results of his tests provided three dates that Conner might have been killed ranging from Dec. 21 to Dec. 24, 2002, DeVore said. He acknowledged that his conclusion could be off by a few days.
When Geragos suggested that using numbers from another study could put Conner’s death as late as Jan. 6, 2003, the doctor noted that the study he referred to was based on diseased babies who died. None of Laci Peterson’s pregnancy tests suggested Conner was anything but healthy, DeVore said.
Testimony will resume this afternoon.