Medscape Medical News 2005. © 2005 Medscape

Oct. 11, 2005 (Washington) — The age-old problem of colic in infants may be more a result of a crying reflex than gastrointestinal upset, a California pediatrician told attendees here at the American Academy of Pediatrics National Conference and Exhibition.

An infant's crying, which can last from minutes to hours, may actually be the result of missing the constant noise and stimulation of the womb, said Harvey Karp, MD, an associate professor of pediatrics at the University of California at Los Angeles Medical School. "This may be the solution to a 3,000-year-old medical mystery of what causes colic."

A new system that involves the five S's — swaddling, side/stomach positioning in the parents' arms, shushing, swinging, and sucking — can calm most crying infants, Dr. Karp said. This activates the baby's calming reflex during the first three to four months of life by mimicking experiences in the uterus.

Most infant crying is not due to an emergency, but the baby's need for attention, he said.
In his theory, infants are evicted from the womb before their "fourth trimester," before they are fully developed, Dr. Karp said. "In many ways, newborns aren't ready for the world at birth and need that fourth trimester for gentle stroking, holding, and shushing."

Past studies have shown that the average infant at six weeks of age cries about 3.5 hours a day, he said. "This results in nursing problems, marital stress, postpartum depression, unnecessary emergency room visits, and shaken baby syndrome.

It has been thought for years that the main cause of colic in infants was due to gastrointestinal problems, but this may not be true, Dr. Karp said. Colic appears to stop after three months and in preterm infants it usually does not begin until two weeks after the due date.

Only about 10% to 15% of cases of colic are caused by milk allergies, Dr. Karp pointed out. While infant acid reflux has been a prime reason cited for colic, a Denver study shows that just one in 50 crying infants in an emergency department had reflux and an Australian study showed only one in 24 crying infants younger than three months had reflux, Dr. Karp cited.

Tightly swaddling a crying infant with its arms down by its side initially may make the crying worse, Dr. Karp warned, but holding the baby on its side and gently jiggling it while supporting the head and neck has an immediate calming influence. Shushing sounds should be added, if necessary, and should be as loud as the infant's crying.

In the womb, fetuses hear a loud whooshing sound — louder than a vacuum cleaner. But after birth, there is silence. "Overstimulation is not nearly as big of a problem as understimulation," Dr. Karp said. "Babies miss the rhythmic, hypnotic sounds and movement."

Infants often fall asleep when nursing or taking a bottle, but parents should wake the infant up a tiny bit when laying the baby down to sleep, Dr. Karp said.

If the five S's are followed, not only will the crying infant stop, but the baby will sleep an extra one to two hours a night, he said.

"If the five S's are done exactly right with just enough vigor, the calming reflex will be turned on and the baby will stop crying," Dr. Karp said. "If a parent can get the baby to stop crying they feel like a million bucks, but if they can't, they feel miserable. Parents need to be taught how to quiet their babies."

Teaching this to parents may be useful, said Karen Miller, MD, an associate professor of pediatrics at Tufts University in Boston, Massachusetts. "But more research needs to be done to show the techniques are safe and effective."

Many of the individual techniques have been found to be valid, Dr. Miller said. "It's the whole package that needs further research before it is endorsed."