Snoring Babies Without Syndromes May Still Have Serious Sleep Apnea, Small Study Finds

When a healthy, full-term baby snores or seems to struggle for breath during sleep, many pediatricians have long assumed the risk of serious sleep-disordered breathing was low. Most research on infant sleep apnea has focused on high-risk groups, such as premature infants or babies with genetic syndromes and underlying medical conditions. A new case series from researchers at the University of Texas Southwestern Medical Center and Children’s Medical Center Dallas, published in Frontiers in Sleep, now suggests that even term, non-syndromic infants referred for evaluation of suspected sleep-disordered breathing can show surprisingly severe disease, with many appearing to outgrow it as they age.

The study, led by Liz E. Lezama Oropeza, with colleagues Elisa Basora-Rovira and Aarti Shakkottai, reviewed polysomnographic data from fifteen infants between zero and twelve months of age who were born at term and had no identified syndromes. The mean gestational age of the cohort was 38.4 weeks, with a narrow spread of plus or minus 0.6 weeks, and eighty percent of the infants were male. The average age at the first sleep study was 7.5 months, with a standard deviation of 3.6 months, meaning the group spanned early infancy through the first birthday.

Polysomnography, the gold-standard overnight sleep test, records brain waves, breathing effort, airflow, oxygen saturation, carbon dioxide levels, and body movements to quantify how often breathing is disrupted during sleep. In this cohort, the average apnea-hypopnea index, or AHI, which counts the number of apneas and hypopneas per hour of sleep, was 23.1 events per hour. The mean obstructive AHI, which isolates events caused by physical blockage of the upper airway, was 20 events per hour, while the mean central apnea index, reflecting pauses in breathing driven by immature or irregular brainstem signaling rather than airway obstruction, was 3.1 events per hour. For context, an obstructive AHI above 5 events per hour is generally considered moderate sleep apnea in pediatric populations, so the average infant in this series fell well into the moderate-to-severe range.

Oxygenation data added another layer of concern. Mean oxygen saturation during sleep was 97.5 percent, but the mean nadir, the lowest saturation reached during any single desaturation event, was 81.0 percent, with a wide standard deviation of 9.9 percent. Six of the fifteen infants met formal criteria for sleep-related hypoxemia, defined in this study as oxygen saturation below 90 percent for at least five minutes during the recording. Carbon dioxide measurements told a different story: mean and peak carbon dioxide levels were 35 and 48.6 millimeters of mercury, respectively, and none of the patients met criteria for sleep-related hypoventilation, which would require elevated carbon dioxide above 50 millimeters of mercury for more than a quarter of total sleep time. The pattern suggests that in these otherwise healthy infants, the dominant problem was intermittent airway obstruction causing repeated oxygen dips rather than sustained underventilation.

The clinical picture preceding referral was often subtle. Only a third of the infants had documented snoring, the symptom most parents and clinicians associate with sleep apnea, and nearly half, forty-seven percent, carried a diagnosis of gastroesophageal reflux, a condition that has been linked to airway inflammation and laryngeal hypersensitivity in infants. Seventy-three percent of the infants underwent some form of upper airway evaluation, such as flexible laryngoscopy, and seven of those evaluations revealed abnormal findings. Laryngomalacia, a condition in which immature, floppy supraglottic tissue collapses inward during inspiration, is the most common congenital cause of stridor and obstructive events in infants and featured among the abnormal findings in this series.

Follow-up polysomnography, obtained in ten of the fifteen infants at an average age of around 13.4 months, provided the study’s most striking finding. Four of the ten infants showed complete resolution of their sleep-disordered breathing without any surgical or device-based intervention. One infant achieved resolution while using continuous positive airway pressure, or CPAP, a machine that delivers a steady stream of pressurized air through a mask to splint the airway open during sleep, but was subsequently lost to follow-up. In the remaining five infants, sleep-disordered breathing persisted but improved. The researchers also examined whether disease severity tracked with age, finding a weak negative correlation between AHI and age, with a Spearman rho of minus 0.31 and a p-value of 0.26, which did not reach statistical significance in this small sample but pointed in the direction of decreasing severity as infants matured.

The authors emphasize that the frequency of moderate-to-severe obstructive sleep apnea in this population is high, but that the clinical implications remain unclear. Diagnostic thresholds for sleep-disordered breathing in infants are poorly standardized, and much of the pediatric literature derives normative values from older children or from high-risk infant populations whose airway physiology differs substantially. The infant upper airway is anatomically distinct: narrow cartilaginous structures, predominantly nasal breathing, high airway compliance, and immature neuromuscular control of the pharyngeal dilator muscles all predispose to collapse during sleep, particularly during active or rapid eye movement sleep when muscle tone falls. As infants grow, the airway enlarges, adenoid and tonsillar tissue relative to the airway changes, and neuromuscular control matures, which may explain why many infants in this series appeared to outgrow their disease.

The study has clear limitations that the authors acknowledge. As a single-center case series of fifteen infants, it cannot establish prevalence in the broader population of healthy term infants, since all participants were referred for suspected sleep-disordered breathing at a tertiary care center. The weak correlation between age and AHI did not reach statistical significance, and the follow-up cohort was small, with five of fifteen infants lacking repeat sleep studies. The authors also note that there is limited data on effective treatment strategies for this group, and that the natural history of untreated moderate-to-severe disease in otherwise healthy infants remains poorly characterized.

Nevertheless, the findings carry practical weight for parents and clinicians. Snoring in a full-term baby without a syndrome is not a reliable screening sign, appearing in only a third of this cohort, and reflux may be a more common companion diagnosis than previously appreciated. The authors conclude that further research is warranted to refine diagnostic thresholds and standardize the diagnostic evaluation and interventions for sleep-disordered breathing in this unique population. Until larger, prospective studies establish normative infant polysomnography values and clarify which infants need intervention versus watchful waiting, the study suggests that clinicians evaluating otherwise healthy infants for suspected sleep-disordered breathing should maintain a low threshold for overnight testing, while recognizing that a substantial share of these babies may simply grow out of it.

Subject of Research: A case series of fifteen term, non-syndromic infants referred for suspected sleep-disordered breathing found high rates of moderate-to-severe obstructive sleep apnea on polysomnography, with many infants outgrowing the condition by follow-up.

Article Title: Correlation between phenotype and polysomnography findings of sleep-disordered breathing in term, non-syndromic infants: a case series study

Article References: Lezama, L., Basora-Rovira, E., & Shakkottai, A. (2026). Correlation between phenotype and polysomnography findings of sleep-disordered breathing in term, non-syndromic infants: a case series study. Frontiers in Sleep, 5, Article 1877709. https://doi.org/10.3389/frsle.2026.1877709

Image Credits: AI Generated

DOI: 10.3389/frsle.2026.1877709

Keywords: infant sleep apnea, sleep-disordered breathing, polysomnography, apnea-hypopnea index, laryngomalacia, gastroesophageal reflux, oxygen saturation, hypoxemia, CPAP, term infants, Frontiers in Sleep, pediatric sleep