It's normal for crying to peak during the second month and then decrease. (Ibraheem Abu Mustafa/Reuters)

Colicky infants who cry excessively may be more common in children of depressed men, Dutch researchers said Monday.

Some infants may cry inconsolably for hours, a well-known and stressful problem for parents. Colic — widely defined as crying three hours a day for at least three days a week — usually gets better on its own between three and five months of age.

In extreme cases, frustration may lead a parent or caregiver to shake an infant, which can cause irreversible brain damage.

In the July 1 issue of the journal Pediatrics, Mijke van den Berg, a child psychiatrist at Erasmus Medical Center in the Netherlands, and colleagues reported a 1.29 times higher risk of excessive infant crying per standard deviation increase in a father's depressive symptoms during pregnancy.

The increased risk was apparent after taking into account a mother's depressive symptoms and other factors, such as the child's gestational age, multiple births and income.

"Our findings indicate that paternal depressive symptoms during pregnancy might be a risk factor for excessive infant crying," the study's authors concluded.

"Although our findings are subject to some limitations and need to be replicated, they emphasize the importance of taking paternal factors into account when studying early infant behaviour such as excessive crying."

Depression before child's birth

Recognizing paternal depression next to maternal depression before childbirth could be beneficial for identifying fathers who need help for themselves and their children.

It's unlikely the baby's crying caused men to be depressed since they were screened for the condition before the child was born, they noted.

The researchers speculated that the link between a father's depression and their baby's colic could be related to:

• Genetics (though false paternity could not be ruled out in the study.)
• Poor interaction between depressed fathers and their infants.
• Indirect stress from marital, family or economic pressures.

The team said the study likely underestimated the link between depression and colic since parents who were depressed during pregnancy may have been less likely to fill in the questionnaires.

In the study, parents were asked to recall how often their children cried, rather than filling in diaries at the time, which is more accurate.

Parents offered information on their infants' crying behaviour for 4,426 or 63 per cent of the children.

In March, a Canadian study noted temporary caregivers, especially men, are the most common perpetrators of shaking.

Pediatricians recommend these coping mechanisms to deal with a crying infant:

• Use calming responses, such as carrying, comforting, walking and talking.
• Put the baby down in a safe place and then walk away to calm yourself.
• Never shake a crying baby.

It's normal for infants to show these behaviours, known as PURPLE:

• Peak patterns, where crying increases, peaks during the second month, then decreases.
• Unexpected timing of prolonged crying.
• Resistance to soothing.
• Pain-like look on the face.
• Long crying bouts.
• Evening and late afternoon clustering.

The Dutch study was funded by the Netherlands Organization for Health Research and Development and Geest-Kract.