A hypothesis for colic is presented by Pediatrician Dr. Harvey Karp with a term defined as “The Missing Fourth Trimester”. This refers to the timeframe of a newborn baby’s first three months, and Dr. Karp’s discovery of the neonatal response, also known as the calming reflex or “off switch” for crying in infants younger than 3 months, which is activated by his solution called “The 5 S’s” technique.
According to most doctors, there are four main theories of the cause of colic:
- gastrointestinal disorders
- difficult temperament
- brain immaturity
- maternal anxiety
However, Dr. Karp lists several rebuttals to these four theories in detail:
- Colic starts at 2 weeks of age; gas starts shortly after birth
- Colic ends at 3 months of age; gas lasts a lifetime. Dr. Karp argues symptoms like gas that are suggestive of intestinal pain are probably an overreaction of an immature neurological system to normal intestinal sensations (e.g., the gastrocolic reflex).
- Colic peaks in the evening; gas occurs all day. Dr. Karp claims evening predominance of crying may be caused by a gradual accumulation of stress throughout the day in the absence of calming rhythmic stimulation which newborns are used to experiencing in the womb.
- Colic is absent from some cultures around the world; gas is not. Dr. Karp explains that the parents in these cultures imitate the womb for the baby all day long with constant holding and rocking and frequent nursing.
- Overfeeding is ruled out, as one of these cultures known as the !Kung San, nurse their children 50 to 100 times a day, but their babies never experience colic.
- The swallowed air theory also doesn’t seem to apply, due to radiographs of fussy babies demonstrating they have more air in the GI tract when they finished crying than when they began to cry.
- The theory of brain immaturity does not match either. Newborns do have immature brains that are incompletely myelinated. They display slow transmission of impulses from the retina to the occipital cortex during the first three months of life, have frequent tremors, irregular breathing, crossing of their eyes, and poor state control. However preemies have very immature state control, and they do not experience colic until after their due date.
- The theory of difficult infant temperament was rebuked by researchers as well through numerous studies which have found the association with temperament to be small.
- In addition, the theory that maternal anxiety is a cause of colic was rebutted by studies with mothers of colicky babies proving they are no more inherently anxious than other mothers, and colic is as common in a couple’s fifth baby as in their first baby. Dr. Karp explains this argues against anxiety playing a role in colic because parents tend to be more anxious with their first baby than subsequent ones.
- Lastly, the cessation of colic after approximately 3 months fits perfectly with Dr. Karp’s theory of the missing fourth trimester.
Dr. Karp notes that while these four theories are aspects of colic, they don’t detail its root cause; which is what he calls the missing fourth trimester. He even states babies are born three months too soon. Whether this is the case or not, we need to consider that upon birth, babies are suddenly extracted from a rhythmic, snug and entrancing environment (the womb) to an environment of sporadic noises, new reflexes and sensations. Therefore it is understandable this may overwhelm infants who have poor state control and thus provoke persistent crying.
The exciting part is the solution Dr. Karp has found to be a calming reflex which takes place involuntarily during the last months of pregnancy. The response puts fetuses in a trance, keeping them head down and motionless. Dr. Karp’s clinical experience has found that the calming reflex can be activated after a baby is born as well, by what he calls “The 5 S’s” – maneuvers that mimic uterine sensations. These techniques include:
- Swaddling, which keeps the baby snug and mimicking the womb’s motionless hold during the last few months during pregnancy
- Side or stomach positioning which halts the Moro reflex as babies aren’t in the supine position
- Shushing to audibly reenact the sound of blood flow fetus’ have heard for their entire life before birth
- Swinging copies the movements the baby experienced inside of the mother
- Sucking, which relocated babies sucking their fingers in utero
I believe every pediatrician, caregiver, and parent should be informed of Dr. Karp’s theory of the missing fourth trimester. In my experience, performing the 5 S’s solution has soothed many babies I’ve cared for and proves to be an important gift every baby deserves in their first few months of their beautiful new life.