Cruise, a longtime Scientologist who introduced Holmes to the faith, is likely to follow Scientology's practice of quiet birth. Followers believe the absence of talk and other noise in the delivery room is more healthful for mother and baby.
No one's saying publicly where baby Cruise will enter the world, but if it is at the actor's Beverly Hills home then noise control might prove a challenge. Buzzing paparazzi are already camped aside the property.
With the little one expected soon, tabloids and gossip Web sites have been rife with chatter about silent birth, spawning much speculation about what it is and isn't.
Some are sure it means the mother can't make a peep during childbirth - forget the popular image of a chaotic hospital-room scene with a laboring woman spewing invectives. Others have claimed silence must be maintained for a full week after the baby is born and that Scientology opposes medical exams for newborns.
According to the tenets of Scientology, known as "Dianetics," words - even loving ones - spoken during birth and other painful times are recorded by the "reactive mind," or subconscious. Those memories, adherents feel, can eventually trigger problems for mother and child.
What the doctrine doesn't say is that laboring moms can't make some noise during delivery.
"We're not going for absolute silence," said self-professed "Scientology mom" Michelle Seward. "If a sound is made, that's OK."
After years studying the faith, established in 1950 by fiction writer L. Ron Hubbard, Seward went the silent route for the birth of her son, Sage, five years ago.
Seward drew up a birth plan and discussed her desire for a wordless delivery with her doctor.
In the hospital delivery room, she used hand signals to communicate with her husband and mother. A nurse tapped her on the shoulder to tell her it was time to push. When a complication arose after 30 hours of labor, the doctor whispered to Seward that she would need an epidural.
"I had a happy, calm baby," she said. "I know it's because of the way I delivered him."
Actress Anne Archer, a Scientologist for 30 years, called the recent speculation about silent birth "ridiculous."
"We just want to keep the environment as calm, quiet and loving as possible," she said. "Any culture in the world would understand that and any woman who's given birth would understand that."