Colic and SIDS

DO NOT WORRY IF YOUR BABY HAS COLIC! THERE IS

NO

PROVEN LINK BETWEEN COLIC AND SIDS

I want to discuss a question that occurred to me more than 30 years ago. The reason that I did not want to discuss this in the past is because there is embedded in the question some frightening implications. But now I think that parents on this blog might clarify or answer the question based on their experiences and those of their friends.

The question is: Does colic or infant fussiness/crying/wakefulness prevent SIDS?

Both colic and SIDS spare the first several days of life. Both occur mostly in the evening/night hours. And both are largely gone by a few months of age. When the individual bouts of colicky behavior end, the baby falls asleep and SIDS is thought to usually occur during a sleep phase. But the medical literature suggests that a more "easy" temperament might be associated with SIDS and the colicky baby has the opposite ("difficult") temperament.

The frightening implication, which I want to emphaisize is not based on solid research, is: Is it possible that an "easy" temperament baby is at an increased risk for SIDS or a colicky baby, when the colic abruptly ends, is at an increased risk for SIDS?

In a paper (Medical Hypothesis 7(9):1193-9, 1981), I wrote that "Four (27%) of the 15 SIDS victims had colic [more than 3 hours/day of irritability, fussiness, or crying occurring more than 3 days/week, and lasting more than 3 weeks], but the spells had disappeared before their deaths." A few parents described how happy they had been to see there child suddenly stop crying/fussing and sleep better only to be devastated days later with SIDS. In other words, in this very small sample, when colic was present, SIDS did not occur. I wondered then if colicky crying represented a wakeful drive to breathe (arousals from sleep) and thus had a protective function. But I could not celebrate the presence of colic as a good thing because of the fear that this was a marker for or a risk factor for the subsequent development of SIDS. Additionally, I recognized the possibility that there might be multiple causes of colic and SIDS so it would be inappropriate to think that all colic was associated with preventing SIDS or all colic might be a risk factor for SIDS when the colic ends . I was a full-time academic pediatrician then working with neonatologists doing research on arousals from sleep and SIDS. I tried to talk to more mothers outside of the published research group who had just recently lost their babies to SIDS about their infant's sleeping and crying behavior prior to SIDS to help decide how to gather data and do further research. But these mothers became so upset during the interviews I did not pursue further research with parents. Perhaps some of you have observations that you can share.

Subsequently, I authored two papers (Journal of Pediatrics 101:307-10, 1982 and 106: 688-90, 1985), about the association between breathing during sleep, infant temperament, and sleep duration that seemed to support a possible association. Although "low parental ratings for the three temperamental features intensity, activity, or threshold were associated with less physical activity during sleep, fewer night wakings, and increased respiratory dysrhythmia during sleep…it should not be concluded that less sensitive infants are necessarily at increased risk for SIDS."

Finally, in 1992, my wife, Linda, and I proposed that elevated serotonin levels are associated with colic and subsequent published research by others showed this to be correct. More recently, in 2010, published data linked low serotonin levels with SIDS. "Serotonin is a hormonal neurotransmitter closely linked to many of the body's vital functions, including the sleeping cycle." So we are back to the subject of sleep!

What are your thoughts? Do any of you know of a clearly colicky child who was still having colicky crying/fussing and then died of SIDS when the colic was still present or did the colic disappear before the SIDS.

Another disturbing thought that I would like your opinions and observations on is whether SIDS, which is more likely to occur in the evening/night hours, is more likely in those infants who are extremely sleep deprived, especially during the day. I want to empnasize that I am not thinking about the normal daytime sleep issues that all of you have experienced but I am thinking of much more extreme nap deprivation that I encountered before I wrote my book. No one on this blog has negleted day time sleep but I have, in the past, encountered parents who never thought of putting forth effort to nap their child. Could SIDS be the final common pathway of such extreme daytime sleep deprivation so that the baby is so totally exhausted by evening or night he cannot make a wakeful drive to breathe?

Marc

Filed under: Colic