Causes
For many years, the number one belief of worried parents, grandparents and doctors has been that colicky crying was a sign of abdominal pain (e.g. intestinal spasm, overfeeding, trapped gas). In fact, even the word "colic" is derived from the ancient Greek word for intestine (sharing the same root as the word "colon"). Today, it is fairly well established that there are a variety of causes of colic symptoms, the most common of which include: stomach gas (possibly due to poor burping or milk flow issues), intestinal gas (pocketed in the intestinal tract), neurological overload (the overwhelmed and overstimulated baby that becomes exhausted) and even a muscular type of colic (perhaps due to muscle spasm and birth trauma). A gastrointestinal (GI) theory of colic seems logical because fussy babies often: grunt/pass gas/double-up/cry after eating; have noisy stomachs; improve with tummy pressure, warmth or massage; may improve with pain medication (e.g. paregoric) or sips of herbal teas used for stomach upset (e.g. mint, fennel). However, 85–90% of colicky babies have no evidence of serious GI abnormality.
Research at Guy's Hospital in 1999 linked one of the causes of colic to lactose intolerance. Colicky babies fed milk pre-incubated with lactase enzyme showed a 40% reduction in colic symptoms.
Some have said that babies cry because they sense their mother's anxiety, but this is highly unlikely. They simply do not have the ability to distinguish a mother's anxiety from depression, frustration, etc. In fact, even though parental anxiety is markedly reduced with successive children, it has been shown that a couple's later children are as likely to be colicky as their first. It is plausible, however, that anxiety may have some relationship to crying through a more circuitous route. Anxious parents are often so unsure of themselves that they jump from one calming intervention to another without doing any technique long enough for it to be effective.
What is clear is that there are various causes of colicky babies other than the obvious gassy causes:
- Fussiness peaks at about 6 weeks and reliably ends by 3–4 months, yet infants continue to experience plenty of burps, flatus, bowel movements, etc. well beyond 4 months of age
- Premature babies—with very immature intestines—have no more colic than full term-ers (despite the fact that their intestines are much more immature). And, when they do get colic it doesn't start until they reach their due date. (In other words, a baby born three months early has the same 10–15% chance of developing colic as a full term baby.) Despite eating, defecation, burping and flatulating every day, he/she will have almost no fussing during the first three months.
- Contrary to the belief that babies cry from swallowed air, X-ray studies reveal that when babies start wailing, they have much less air trapped in their stomachs than they do after the colic is over and they are calm and relaxed. (Babies gulp air while crying. So they have more air in the stomach after crying, but it is totally innocuous.)
- "Burp" drops (simethicone) are no better at reducing crying than drops of distilled water.
- Car rides and vacuum cleaner sounds may calm fussing, yet have no power to lessen GI pain.
- In 90% of cases, colic is unrelated to a baby's diet. However, in 10% of cases colic is triggered by stomach discomfort from food allergy and requires altering the diet of a breastfeeding mom or switching a baby to a hypoallergenic formula (e.g. Pregestimil). The most problematic foods for fussy babies seem to be cow's milk based formula and, for breastfeeding babies, dairy products in the mother's diet. Other, less common allergens are wheat, soy and nuts. Breastfed babies may also become fussy from stimulants in the mother's diet (see section on treatment). Parents and doctors commonly switch fussy babies to a soy formula; however, it is not clear that soy reduces colic.
Also, unlike older children and adults who have GI discomfort from lactose intolerance, there is little evidence that this causes crying among infants. However later research, initially by Professor Kearney at Cork University Hospital (published 1995) and then by Dr Dipak Kanabar at Guy's Hospital in London clearly demonstrated that infant colic was linked to transient lactose intolerance and could be controlled by pre-incubating the baby's feed with lactase enzyme. This is now the preferred method of treating colic in UK and Ireland using commercial lactase enzyme drops sold over-the-counter or on NHS prescription.
Some reports have associated colic to changes in the bacterial balance in a baby's intestine. They suggest treating the crying with daily doses of probiotics, or "good bacteria" (such as Lactobacillus acidophilus or Lactobacillus reuteri). In a 2007 study, 83 colicky babies given the probiotic Lactobacillus reuteri had reduced crying time. After one week, treated babies had 19% less crying time (159 min/day vs. 177 min/day). By 4 weeks, treated babies had 74% less crying (51 min/day vs. 145 min/day). In a 2010 study conducted with the same probiotic strain, similar benefits were seen in colicky infants. However, another study found no reduced colic in over 1000 babies who were given a mixture of four other probiotic strains from birth.
In 2009, a University of Texas study observed that colicky babies had a higher incidence of mild intestinal inflammation and a specific intestinal bacteria, Klebsiella. But, a commentary in the same journal, noted that the inflammation and bacteria were most likely just an exaggerated variation of normal.
One study demonstrated higher incidence of colic among breast fed infants, bringing a possibility that stress hormones excreted into the breast milk were causing intestinal cramps. Child birth and breastfeeding can be very stressful and association with stress and intestinal discomfort are well known. Infants with colic have elevated level of cortisol indicating higher level of stress.
A study of prenatal maternal cortisol levels has validated the hypothesis of maternal stress as a potential cause of colic. The researchers found that infants whose mothers had high prenatal cortisol levels displayed more crying, fussing, and negative facial expressions during a series of videotaped bath sessions done between one and twenty weeks of age.
Another study found correlations between maternal depressive symptoms during pregnancy and infant crying. Mothers who had been more depressed had infants who cried more. Similar correlations were found between maternal anxiety levels during pregnancy and amount of crying in the infants at five weeks of age. The mothers with higher prenatal anxiety levels were more likely to have infants with colic. General psychosocial distress during pregnancy has also been found to correlate with infantile colic.
Birth complications may have a direct impact on the infant. Researchers have found correlations between childbirth complications and amount of infant crying. More stressful deliveries were linked to more crying.
Insufficient physical contact after birth may be a contributing factor to infant colic. In a controlled experimental study, infants who were held/carried an extra two hours per day cried significantly less at six weeks of age than those who were offered two extra hours per day of visual stimulation. Another study found increased crying in infants whose mothers affirmed a perceived risk of spoiling young infants with too much physical contact.
T. Berry Brazelton has suggested that overstimulation may be a contributing factor to infant colic and that periods of active crying might serve the purpose of discharging overstimulation and helping the baby’s nervous system regain homeostasis.
Aletha Solter corroborates Brazelton’s theory that some crying represents a beneficial discharge process, and has proposed a more general stress release theory of infant crying. She has hypothesized six major contributing factors to infant colic: 1) Prenatal stress and birth trauma, 2) Unfilled needs (especially the need for physical contact), 3) Overstimulation, 4) Developmental frustrations, 5) Physical pain (including intestinal discomfort), and 6) Frightening events.
Over the past 15 years, many thousands of fussy babies have been given medicine in the belief that their colic was caused by painful acid reflux, so-called gastro-esophageal reflux disease (GERD). From 1999–2004, the use of a popular class of liquid antacid (proton pump inhibitor, or PPI) in young children increased 16 fold. And, from 2000–2003 there was a 400% increase in the number of babies treated with anti-reflux medicines. By all accounts this rate of increase has continued—or accelerated—from 2003 to the present.
In truth, most babies have mild reflux, often referred to as "spitting up." Over the past 5 years, several studies have proven that GERD rarely causes infant crying. Even crying during feeding and crying accompanied by writhing and back arching is rarely related to acid reflux, unless the baby also has:
- 1) poor weight gain (less than 15 gram/day)
- 2) vomiting more than 5 times/day; or
- 3) other significant feeding problems.
A multicenter study, organized by researchers at Pittsburgh Children's Hospital, concluded that GERD medicine is no better than plain water at reducing infant crying. Surprisingly, 50% of fussy babies improved on medicine, but so did 50% of fussy babies given the placebo. In the meantime, research has shown that proton pump inhibitors can cause decreased bone density in adults. No research has been done on bone density or growth in children given PPIs and this use is not approved by the FDA and should be considered experimental.
Read more about this topic: Baby Colic