Oct. 27, 2004 -- The relentless, full-throttle crying of colic is worrisome for parents. But only in rare cases, when crying persists past 3 months old, it may be a sign of trouble, new research shows.
The report appears in the latest issue of Archives of Diseases in Childhood.
Colic is indeed a source of parents' frustration, because nothing seems to relieve it. Doctors say some babies are colicky because of a sensitive temperament, and because their nervous system is immature. As babies grow and develop, they can better control their crying. Within their first eight weeks, the frequency and intensity of their crying gradually decreases.
"Colic is common among infants ... extremely stressful for families ... [but] usually resolves itself within the first three months, with no apparent affect on brain development," writes researcher Malla R. Rao, PhD, an epidemiologist formerly with the National Institute of Child Health and Human Development, now with the National Institute of Allergy and Infectious Diseases.
However, a handful of studies have shown that persistent crying -- longer than three months - may be related to mental and behavioral problems as children get older, Rao says. In a recent study, children who still had unexplained, persistent crying beyond six months tended to be hyperactive when they reached 8-10 years old.
Colic vs. Persistent Crying
In their study, Rao and colleagues in Norway and Sweden investigated this pattern. They tracked the progress of 327 pregnant women and their newborn infants, from the second trimester until the child was 5 years old. All the infants were otherwise healthy babies.
Also, all the mothers were "veterans" having raised at least one infant already. They could easily distinguish between abnormal and normal crying, says Rao.
Public health nurses checked the infants at 6 and 13 weeks old, and at 6 and 9 months old for signs of colic, defined as unexplained daily and prolonged infant crying for at least two weeks reported within the first 12 weeks of life but not beyond. "Prolonged crying" was defined as daily, uncontrolled, prolonged crying without any obvious cause, persisting for at least two weeks but reported at both six-week and 13-week visits. When each child turned 5 years old, the child's mother provided a detailed history of the child's major health problems.
In this group, 48 infants had colic, and 15 had prolonged crying that persisted past 13 weeks, Rao reports.
Children who had a history of prolonged crying as infants, but not those that had colic, had poorer outcomes in tests of thinking skills.
Prolonged criers had these problems:
- Three of the 15 children (20%) had IQ scores nine points lower than a comparison group of children whose mothers reported no crying-related problems. This was not noted for children with colic.
- Five children had significantly poorer fine-motor abilities, such as hand-eye coordination, when compared with children whose mothers reported no crying-related problems.
- These children were also more likely to have problems associated with discipline and with hyperactivity. Nine children had discipline and hyperactivity problems. These problems were not seen in children with colic.
Infants in his study had no unusual signs of toxins -- or nutritional deficiencies -- in their blood tests, he notes. The infants also had no major health problems that could account for their crying, and their home environments were similar.
"When we looked at the children who had typical colic, as expected we saw no problems later," he tells WebMD. "But on average, the persistently crying children had lower IQ, poorer fine-motor skills, and more behavior problems." The prolonged crying itself may be an indication of later brain development problems, he explains.
Prolonged Colic, Mental Deficits Are Rare
"I don't want parents to go crazy worrying about this... The good news is, most infants in this study had garden-variety colic, and they were fine. In general, colic goes away and this study does not imply otherwise," says Steven Parker, MD, director of behavioral and developmental pediatrics at Boston Medical Center and professor of pediatrics at Boston University School of Medicine. Parker also writes a biweekly column for WebMD's Parenting and Pregnancy channel.
"If crying lasts over six months, it's worthwhile for a pediatrician to try to figure out what it's due to," Parker tells WebMD. "In some kids, it may be a medical problem like heartburn or reflux, and they end up being OK. In a small percentage, there may be something going on in the nervous system. Early intervention for these kids would help them."