SIDS "Back to Sleep" Campaign and Developmental Delays

In 1992, the American Academy of Pediatrics (AAP) recommended that healthy infants be positioned to sleep on their back (supine position) or side (lateral position) when being placed down for sleep to reduce the risk of Sudden Infant Death Syndrome (SIDS).(1) The reason for this recommendation was that epidemiological studies had reported an association between infants who were positioned to sleep on their front (prone position) and SIDS. The AAP’s 1992 recommendations were announced five years after the Netherlands had started it’s infant supine sleep position campaign in 1987.(2,3) The Netherlands recommendations were followed by infant supine sleep position campaigns in the United Kingdom, New Zealand, and Australia in 1991, the U.S. and Sweden in 1992, and Canada in 1993.(4,5) In 1994 a number of organizations in the United States combined to further communicate these supine sleep position recommendations and this became formally known as the “Back To Sleep” campaign.(6) In 1996, the AAP further refined its sleep position recommendation by stating that infants should only be placed to sleep in the supine position. But, these public health campaigns to educate mothers on how to position infants in bed, while successful, may have unintended negative consequences.(7)

In 1992, the first National Infant Sleep Position (NISP) Household Survey was conducted to determine the usual position in which U.S. mothers placed their babies to sleep: 1. Lateral; 2. Prone; 3. Supine; 4. Other; 5. No Usual Position.(8) According to the 1992 NISP survey, 70.1% of infants were positioned in the prone position to sleep and 13.0% of infants were positioned in the supine position for sleep.(9) In 1999, the NISP survey reported that 13.4% of infants were positioned in the prone position to sleep and 64.7% of infants were positioned in the supine position to sleep.(10)

Since 1998 there have been several studies published which report that infants placed to sleep in the supine position lag in motor skills, social skills, and cognitive ability development when compared to infants who sleep in the prone position.(11,12,13) In the 1998 article entitled “Effects of Sleep Position on Infant Motor Development” by Davis, Moon, Sachs, and Ottolini, the authors state “We found that sleep position significantly impacts early motor development.”(14) The authors also stated that “The pattern of early motor development is affected by sleep position. Prone sleepers attain several milestones earlier than supine sleepers. However, all infants achieved all milestones within the accepted normal range. Pediatricians can use this information to reassure parents. This difference in milestone attainment is not a reason to abandon the American Academy of Pediatrics’ sleep position recommendations.” The prone sleeping infants in this study slept an average of 225.2 hours (8.3%) more in their first 6 months of life than the supine sleeping infants.

In the 1998 article entitled “Does the Supine Sleeping Position Have Any Adverse Effects on the Child? II. Development in the First 18 Months” by Dewey, Fleming, Golding, and the ALSPAC Study Team the objective of the study was “To assess whether the recommendations that infants sleep supine could have adverse consequences on their motor and mental development.”(15) They utilized the Denver Developmental Screening Test (DDST) and studied infants at 6 and 18 months. According to the study, at 6 months of age, the infants who were placed to sleep in the prone position had statistically significant higher social skills scores, gross motor scores, and total development scores than those infants who were put to sleep in the supine position. In addition, the total development scores of prone sleeping infants were still higher than supine sleeping infants at 18 months of age but were no longer statistically significant. The article concluded that “There is some evidence that putting infants to sleep in the supine position results in a reduced developmental score at 6 months of age, but this disadvantage appears to be transient. Weighing this against the adverse health effects demonstrated with the prone sleeping position, these results should not change the message of the Back to Sleep Campaign.” Both articles cited in regards to the “adverse health effects” of the prone position were either solely authored or co-authored by members of this research team.

In the 2005 article entitled “Influence of supine sleep positioning on early motor milestone acquisition” by Majnemer and Barr they utilized the Alberta Infant Motor Scale Scores (AIMS Scores) to analyze the impact of infant sleep position.(16) They reported that “Typically developing infants who were sleep-positioned in supine had delayed motor development by age 6 months, and this was significantly associated with limited exposure to awake prone positioning.” The authors also theorized that an infants awake positioning was associated with their sleep position. The authors state in the Discussion section that “Recommendations promoting supine sleep positioning have reduced the incidence of Sudden Infant Death Syndrome and should in no way be modified by the results of this study.”

In a March 2007 article entitled “New reference values for the Alberta Infant Motor Scale need to be established” by Fleuren, Smit, Stijnen, and Hartman of the Erasmus MC Sophia Children’s Hospital in Rotterdam, Netherlands, the authors reported their analysis of the motor performance, using the AIMS scale, of 100 Dutch children.(17) The AIMS scores used were developed by Piper and Darrah and calculated for Canadian Children between 1990 and 1992. It should be noted that the first infant supine sleep position campaign in Canada began in 1993 and these AIMS scores were calculated before Canada began it’s 1993 supine sleep campaign.(18) Also, this study comes 20 years after the first supine sleep campaign began in the Netherlands in 1987.(19) According to the Fleuren, Smit, Stijnen, and Hartman study the results showed that “The percentile scores of the group were significantly lower than scores of the Canadian norm population (p<.001), whereby 75% of the Dutch children scored below the 50th percentile. These lower scores were not explained by sex, racial differences or congenital disorders and were seen in all age groups.”(20) According to the aricle “Motor Profile of Children with Developmental Speech and Language Disorders” by Visscher, Houwen, Scherder, Moolenaar, and Hartman, 51% of children with Developmental Speech and Language Disorders ( DSLD’s) had definite or borderline motor problems.(21)

Since the 1990’s there has also been a reported increase in the United States of cases of Plagiocephaly which is sometimes called “Flattened Head Syndrome” in the media.(22,23) In 1974, plagiocphaly was estimated to have occurred in one out of every 300 live births.(24) Following the “Back To Sleep” campaign the occurrence of plagiocephaly increased to 1 in every 60 children in 1996.(25) In one study it was reported that this incidence level has increased to 1 in 12 infants.(26) According to the paper “Prevention and Management of Positional Skull Deformities in Infants” by Persing, James, Swanson, Kattwinkel, et al “The increasing incidence of deformational plagiocephaly is likely related to the recommendation of the American Academy of Pediatrics (AAP) and others that infants be placed to sleep on their backs.”(27) In an interview with the UK newspaper the Guardian regarding this study, Peter Fleming (whom the Guardian cites as “an expert in cot deaths” and is a co-author of the Dewey, Fleming, Golding, and ALSPAC Study Team article referred to on page 2) was quoted as saying about deformational plagiocephaly that “I do not think it is a medical problem - it is more of a cosmetic one. Mothers may feel it is a syndrome and a problem when it really is nonsense.”(28) According to the article “Neurodevelopmental delays in children with deformational plagiocephaly” by Kordestani, Patel, Bard, Gurwitch, and Panchal “Infants with deformational plagiocephaly were found to have significantly different psychomotor development indexes and mental developmental indexes when compared with the standardized population."

In the article “Prone or Supine Body Position and Sleep Characteristics in Infants” by Kahn, Grosswasser, Sottiaux, Rebuffat, Franco, and Dramaix the authors state that infants positioned to sleep in the prone position compared to supine sleeping infants slept 16% longer overall, had a 25% increase in non-rapid eye movement sleep (NREM), had 40% less arousals, and when there was an arousal it was 43% shorter.(32) For the study “Behaviour and physiological responses during prone and supine sleep in early infancy” by Skadberg and Markestad, the authors studied infants at 2.5 months and 5 months of age and reported that at both 2.5 and 5 months of age prone positioned infants when compared to supine sleeping infants had less arousals, less body movements, less sighs, and less episodes of apnea during Rapid Eye Movement sleep (REM) sleep.(33) These two studies show that the supine sleep position increases apnea episodes and decreases sleep duration in infants. The negative effects cause by increased apnea episodes, intermittent hypoxia, increased sleep fragmentation, and a lowering of sleep duration cannot be mitigated by supervised prone awake positioning of the infant.

Although it is difficult to quantitatively assess the effect of increased apnea episodes on infants the negative effects on children have been analyzed. In the study “Learning in children and sleep disordered breathing: Findings of the Tucson Children’s Assessment of Sleep Apnea (TuCASA) Prospective Cohort Study”, Kaemingk, et al studied 149 children between the ages of 6 and 12.(34) They tested the hypothesis that the group which contained participants with an apnea/hypopnea index (AHI) of 5 or greater (n=77) when compared to a group with an AHI of less than 5 (n=72) would have weaker performance when assessing intelligence, learning, and memory, as well as academic achievement. Their research determined that there was a negative relationship that existed between AHI and Full Scale IQ, math achievement, and immediate recall. In addition, a lower Performance IQ was associated with hypoxemia. The research, they conclude, points to the suggestion that nocturnal respiratory disturbance is a factor associated with a decrease in learning in children who were otherwise healthy, sleep fragmentation has an adverse impact on memory and learning, and that hypoxemia has an adverse influence on nonverbal skills.

Although not specifically related to infants the following article details how sleep position impacts males and females differenly. n the article “Gender Differences in the Polysomnograpic Features of Obstructive Sleep Apnea” by O’Connor, Thornley, and Hanly, the researchers analyzed 830 patients who had been diagnosed with OSA in a retrospective study.(35) They used the apnea-hypopnea index (AHI) and total sleep time to group patients in three OSA categories: (1) mild (5 to 25 events/h), (2) moderate (26 to 50 events/h), and (3) severe (>50 events/h). They then analyzed the OSA differences during different stages of sleep by determining the AHI for non-rapid eye movement sleep (NREM) (AHINREM) and the AHI for rapid eye movement sleep (REM)(AHIREM) and comparing the two results. They reported that for the most severe cases of OSA the ratio was 7.9 men for every 1 woman. Based upon this study they derived 4 conclusions: (1) OSA is not as severe in women because OSA is milder during NREM sleep; (2) Women have an increase in clustering of respiratory evens in REM sleep when compared to men; (3) OSA during REM sleep is disproportionately greater in women than men; (4) OSA occurs at a disproportionately higher rate in men when sleeping supine than when women sleep supine. According to Ryan and Bradley in their article “Pathogenesis of Sleep Apnea”, the most important pathophysiological feature related to the OSA condition is the collapse of the upper airway (UA) at the pharynx level during sleep.(37) According to the authors, the pharyngeal muscles maintain responsibility for movement of the hyoid bone, pharynx, soft palate, tongue, and uvula and that they also subserve several other functions such as coughing, deglutition, phonation, and respiration. They further state that women appear to be protected from OSA at least in part because compared to men their UA is less collapsible.

In addition to the above studies analyzing the effects of sleep position and sleep apnea, the article “Obstructive Sleep Apnea in Infants and Its Management With Nasal Continuous Positive Airway Pressure” by McNamara and Sullivan analyzes the effect on infants that using nCPAP (nasal Continuous Positive Airway Pressure) has on infants with OSA.(38) Although the study had only 24 participants some of the outcomes are interesting to note. According to the authors, the parents in the study commented that following nCPAP therapy for OSA there was a notable improvement in their infant’s daytime behavior. They described these improvements as their infant being more alert while they were awake and being able to complete feeding more easily without rests. In addition, three of the infants in the study had failure to thrive at the same time of the OSA diagnosis. But, within 3 months of beginning nCPAP therapy they had rapid increases in both their height and weight. Therefore the treatment of OSA in these 3 infants, although not statistically significant, was associated with an increase in growth velocities. According to the researchers, 3 other infants were discontinued on the nCPAP therapy due to parental non-compliance in the study. One of these infants was treated with surgery and the other two were treated by positioning them to sleep in the prone position. According to the American Academy of Pediatrics article “Clinical Practice Guideline: Diagnosis and Management of Childhood Obstructive Sleep Apnea” symptoms that are associated with Obstructive Sleep Apnea in infants greater than one year of age include restless sleep, daytime neurobehavioral abnormalities, daytime sleepiness, and growth abnormalities.(39)

Considering that developmental delays have been reported to be caused by the supine sleep position a consideration of the positive and negative impact of infant sleep positioning practices is important. According to the 1997 article entitled “Does the Supine Sleep Position Have Any Adverse Effects on the Child? I. Health in the First Six Months” by Hunt, Fleming, Golding, and the ALSPAC study team prone sleeping infants were more likely to have coughs, pyrexia episodes, signs of eczema, general practitioner visits, earaches, hearing problems, colic, and crying problems compared to supine sleeping infants.(40) Whether the prone sleeping position caused these problems or children were put in the prone position sleeping position to alleviate these problems was not determined in the study. They found only 2 negative effects for infants who sleep in the supine position: “These relationships are for an increase in nappy (diaper) rash at 4 weeks of age and cradle cap at 6 months of age. Neither are likely to cause major concerns to health professionals.” A co-author of this study, Dr. Peter Fleming, is credited in a University of Bristol press release as helping to implement the SIDS prevention “Back to Sleep” campaign in over 30 countries which has prevented over 100,000 infant deaths worldwide.(41) The follow-up study to this one, as previously mentioned, found “adverse health effects” to children to be “transient” based upon the Denver Developmental Screening Test.

Other studies have found the following negative conditions that the supine sleep position has been reported to be associated with are: Gross Motor Milestone Delays, Shoulder Retraction, Positional Torticollis, Increase in Sleep Apnea, Decrease in Sleep Duration, Deformational Plagiocephaly, Strabismus, Social Skills Delays, and Temporomandibular Jaw Difficulties.(42) In addition, the following are symptoms that are associated with sleep apnea: growth abnormalities, failure to thrive syndrome in infants, neurocognitive abnormalities, daytime sleepiness, emotional problems, decrease in memory, decrease in learning, and a delay in nonverbal skills. The conditions associated with deformational plagiocephaly include visual impairments, cerebral dysfunction, delays in psychomotor development and decreases in mental functioning. The conditions associated with Gross Motor Milestone Delays include speech and language disorders. In addition, it has been hypothesized that delays in motor skills can have a negative impact on the development of social skills.(43,44) In addition, other studies have reported that the prone position prevents subluxation of the hips, increases psychomotor development, prevents scoliosis, lessens the risk of gastroesophageal reflux, decreases infant screaming periods, causes less fatigue in infants, and increases the relief of infant colic.(45) In addition, prior to the “Back to Sleep” campaign many babies self-treated their own torticollis by turning their heads from one side to the other while sleeping in the prone position.(46) Supine sleeping infants cannot self-treat their own torticollis.

Between 1992 and 1999 the rate of SIDS in the United States decreased by greater than 45%.(47) Also, according to the CDC, there are known to be a number of risk factors associated with SIDS other than supine sleeping.(48) These are: soft sleep surfaces, loose bedding, overheating, maternal smoking while pregnant, having a smoker in the household, pre-term birth, low birth weight, and bed sharing. The maternal pregnancy smoking rates in the U.S. decreased by 38% between 1990 and 2002.(49) Also, according to an analysis by the Scripps Howard News Service some of the reported decrease in SIDS rates may be due to “code shifting” and according to their research “Coroners and medical examiners said SIDS was responsible for nearly 80 percent of all sudden infant deaths 15 years ago and only 55 percent in 2004.”(50) Based upon the available evidence it’s likely that the influence of the infant supine sleep position on the decrease in SIDS rates is likely very much overstated.

If the U.S. supine sleep position rates continue at their current level (75.7% in 2006 compared to 13.0% in 1992) the negative health outcomes associated with supine sleep will continue.(51) But, the effect of the “Back to Sleep” campaign is important to consider from a global perspective too considering that between 1987 and 1993, Australia, Canada, the Netherlands, New Zealand, Norway, Sweden, and the United Kingdom also began infant supine sleeping campaigns.(52,53) Although supervised awake prone positioning and regular head re-positioning for sleep may mitigate some of the negative consequences of the supine sleep position they will do nothing to mitigate the negative effects caused by and associated with decreases in sleep duration, increases in apnea (hypoxemia) episodes, and increases in sleep fragmentation. In summation, it is my conclusion that during the prenatal and postnatal time periods parents should be educated on both the pros and cons of the various infant sleep positions rather than simply being told "Back to Sleep" and "Tummy to Play".

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