London, Apr 3 (IANS): Parents in Canada, Britain and Italy have to deal with greater crying and fussing by their babies than those in many other industrialised nations, new research has found.

Struggling with wailing babies is least common in Denmark, Germany and Japan, the study, published in The Journal of Pediatrics, found.

"Babies are already very different in how much they cry in the first weeks of life -- there are large but normal variations. 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," said Dieter Wolke, Professor at University of Warwick in Britain.

As childcare and the family unit has largely transformed over the last half century and across different cultures, new universal guidelines were needed for modern parents and health professionals to assess normal and excessive levels of crying in babies.

So Wolke formulated universal charts for the normal amount of crying in babies during the first three months.

In an analysis of studies involving almost 8700 infants -- in countries including Germany, Denmark, Japan, Canada, Italy, the Netherlands and Britain -- Wolke calculated the average of how long babies fuss and cry per twenty-four hours across different cultures in their first twelve weeks.

On average, it was found that babies cry for around two hours per day in the first two weeks.

Crying generally peaks at around two hours fifteen minutes per day at six weeks -- and reduces gradually to an average of 1 hour 10 minutes by the twelve week mark.

However, some infants were found to cry as little as 30 minutes, and others over five hours, in twenty-four hours.

The highest levels of colic -- defined as crying more than three hours a day for at least three days a week in a baby - were found in Britain, Canada and Italy.

In contrast, lowest colic rates were reported in Denmark, Germany and Japan.

The current definitions for determining whether a baby is crying too much and suffering from colic, are the Wessel criteria, which were formulated in the 1950s.

"The new chart of normal fuss/cry amounts in babies across industrialised countries will help health professionals to reassure parents whether a baby is crying within the normal expected range in the first three months or shows excessive crying which may require further evaluation and extra support for the parents," Wolke said.