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A firm recommendation: measuring the softness of infant sleep surfaces
Sheena H Gillani1, Gina S Lowell2, Kyran P Quinlan2
1Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Rd, North Chicago, IL, 60064, USA. sheena.gillani@my.rfums.org.
Insights
Infant sleep surfaces vary widely in softness, with some as soft as adult mattresses. Adding bedding like blankets and pillows significantly increases surface softness, impacting sudden unexpected infant death (SUID) risk.
Area of Science:
- Pediatric safety engineering
- Infant sleep environment research
- Biomechanical testing of sleep surfaces
Background:
- Sudden unexpected infant deaths (SUID) pose a significant risk, with unintentional suffocation in bed accounting for a quarter of cases.
- Soft bedding is a major risk factor for SUID, yet objective definitions for infant sleep surface firmness are lacking.
- The American Academy of Pediatrics (AAP) recommends firm sleep surfaces, but lacks standardized measurement criteria.
Purpose of the Study:
- To evaluate the performance of a novel device designed to quantify infant sleep surface softness.
- To establish objective softness values for various common infant sleep surfaces.
- To provide data that can inform the development of national safety standards for infant sleep products.
Main Methods:
- A custom device was engineered to measure vertical head depression (softness) on sleep surfaces, simulating a 2-month-old infant.
- Seventeen sleep surfaces, including 14 household items and 3 hospital mattresses, were tested between April 2019 and January 2020.
- Measurements were also taken with added soft bedding, such as infant fleece blankets and pillows, to assess their impact on surface softness.
Main Results:
- Household infant sleep surfaces exhibited a wide range of softness (7.4–36.9 mm), with some comparable to adult foam mattresses and sofas.
- Adding an infant fleece blanket incrementally increased surface softness, with three folds adding up to 21.8 mm.
- Pillows significantly increased softness, with soft pillows adding up to 46.4 mm, highlighting their potential risk.
Conclusions:
- A broad spectrum of softness exists among infant sleep surfaces, with some posing risks similar to adult products.
- The addition of blankets and pillows demonstrably increases sleep surface softness, exacerbating potential SUID risks.
- Quantifying sleep surface softness is crucial for advancing SUID risk understanding and informing improved infant sleep safety recommendations and national mattress standards.
Background:
Approximately 3600 sudden unexpected infant deaths (SUID) occur annually in the United States, and a quarter of SUIDs are caused by unintentional suffocation and strangulation in bed, with soft bedding use being a significant risk factor. Therefore, The American Academy of Pediatrics (AAP) recommends infants sleep on a "firm" surface, though neither an objective definition nor national standard has been established. The purpose of this study is to report on the performance of a device that measures mattress softness and to provide quantitative values of softness for various infant sleep surfaces.
Methods:
In collaboration with the authors and a national child product safety organization (Kids in Danger), University of Michigan engineering students designed and validated a device that measures the vertical depression (softness) of a simulated 2-month-old's head on a sleep surface. A total of 17 infant sleep surfaces - 14 household surfaces and 3 hospital mattresses - were measured between April 2019 and January 2020. The average softness of each surface was calculated. Surfaces were also measured with soft bedding, which included an infant fleece blanket, and firm and soft pillows.
Results:
The average softness for the 14 household sleep surfaces ranged from 7.4-36.9 mm. The 2019 cribette playard and the 2018 infant spring had similar softness (21 mm) as the 2018 and 2019 adult foam and 2015 sofa. An infant's fleece blanket folded once added an additional 2.3-6.5 mm of softness, folded twice added 4.8-11.6 mm, and folded three times added 11-21.8 mm. Using a firm pillow added 4.0-20.9 mm of softness while using a soft pillow added 24.5-46.4 mm. The softness for the 3 hospital sleep surfaces ranged from 14 to 36.9 mm, with the infant bassinet being the firmest and the pediatrics mattress being the softest.
Conclusions:
We found a wide range of softness among sleep surfaces, with some infant mattresses as soft as some adult mattresses. Adding blankets and pillows to mattresses measurably increased softness. Quantifying sleep surface softness will advance our understanding of how softness relates to SUID risk. We hope this new information will further inform safe infant sleep recommendations and improve mattress safety standards nationally.
