"You have to collaborate with your doctor, but be informed," said Walker-Lewis of the ever-changing field of medicine and child rearing where advice changes on a dime.
But now the New Jersey mother-to-be, who is "ready to go" and expecting a boy in October, has one more thing to worry about -- whether her son will have a flat head.
New research confirms what doctors have seen in a generation of babies -- that 1 in 40 babies who sleep on their backs will develop a flat head, making them more prone to ear infections and long-term complications such as language disorders and learning disabilities.
The study, published in the September issue of The Journal of Craniofacial Surgery, warns about a 49 to 54 percent increase in ear infections in a skull deformity known as deformational or positional plagiocephaly.
"It's been around since the mid-'90s and it's pretty common these days," said Dr. Lisa David, senior researcher on the Wake Forest University Medical Center study.
"It's just one more thing to research and discuss the risks and benefits," said Walker-Lewis, who works in the fashion business. "Circumstances change and risk factors change."
Each year in the United States, more than 4,500 infants die suddenly of no obvious cause. About half of them are attributable to Sudden Infant Death Syndrome (SIDS), the leading cause of death among infants 1-12 months old, according to the Centers for Disease Control and Prevention.
Doctors still don't know what causes SIDS, but suspect that it may have something to do with abnormalities in the part of the brain that control breathing and waking during sleep, according to First Candle/SIDS Alliance, a health organization committed to infant survival.
These flaws could stem from exposure to toxins or lack of oxygen in the prenatal stage, they say.
It is also thought that sleeping on the stomach, with the baby's airway so close to the mattress, could affect oxygen intake by rebreathing. Pediatricians say some babies just "forget" to breathe.
The so-called Back to Sleep campaign -- warning parents about the dangers of babies sleeping on their stomachs -- was launched in 1994 with an effort to reach every newborn in the nation.
Since then, doctors have seen more cases of flat head, the result of pressure on the skull from lying in the same position. Treatment consists of a helmet or band to gently mold the growing skull back into shape.
Earlier detection is key -- before four months of age. After that, sleep patterns have been established and flat heads are "self-perpetuating," and treatment is longer, according to David, a craniofacial surgeon.
"Imagine wearing a bun or a pony tail," she said. "When an area of their skull sticks out, they gravitate toward the flat side. The more comfortable it is, the flatter it gets."
Across the board, doctors stress that back sleeping has saved so many babies that parenting advice is not likely to change.