Crying: it's what babies do. But sometimes this perfectly normal noisemaking signals that something is wrong. According to the American Academy of Pediatrics, in their first weeks of life at least 10 percent of babies in the United States are diagnosed with colic, a condition characterized by excessive crying and linked to a higher risk of child abuse and postpartum depression.
The number of colicky, but otherwise healthy, babies in the U.S. is nothing compared to the bawling babes of some other industrialized nations. A new study published in the Journal of Pediatrics examined the crying, fussing and colic duration of babies around the world. Dieter Wolke, a psychology professor at the University of Warwick in the United Kingdom, performed the meta-analysis of 8,690 infants with the participation of parents who tracked their children's behavior with 24-hour diaries.
Using the data, Wolke calculated the average length of time babies cried or fussed in their first 12 weeks of life. He discovered that most babies cried about two hours a day for their first two weeks, and then ramped up the fussiness at the six-week mark by crying two hours and 15 minutes. By the time the babies reach 12 weeks, however, the crying has greatly subsided and averaged about one hour of every 24-hour period.
Wolke ranked the countries in the study by measuring babies' colic levels using the Wessel "rule of threes" criteria, a diagnostic tool named for Yale professor Morris Wessel, who coined the medical definition of colic in 1954. The "rule of threes" refers to a baby who cries for more than three hours a day on least three days in any one week.
The study found that babies in Canada, Italy and the United Kingdom cry the most. Canadian babies lead the way with 34 percent of 4-week-olds crying inconsolably, followed by 2-week-olds in the U.K. at 28 percent, and Italian 9-week-olds at 20 percent.
Meanwhile, babies in Denmark, Germany and Japan cry the least. Only 5.5 percent of Danish babies are colicky, followed by German babies at 6.7 percent and Japanese babies at 2 percent. American babies, as far as crying goes, are solidly average.
In a statement, Wolke said he hopes the newly calibrated colic data "will help health professionals to reassure parents, whether a baby is crying within the normal expected range in the first 3 months, or showing excessive crying that may require further evaluation and extra support for the parents."
As for the baby whisperers in Denmark? The low colic rate of babies may be linked to the country's parenting style. Earlier studies, including one by Ian St. James-Roberts at the University of London, found that Danish parents hold their babies at least 10 hours a day, including at least six hours when the babies are awake.
"Babies are already very different in how much they cry in the first weeks of life," Wolke said. "We may learn more from looking at cultures where there is less crying and whether this may be due to parenting or other factors relating to pregnancy experiences or genetics."