Dr Jane Williams, Bindy Cummings and Dr Tessa Grigg
At GymbaROO-KindyROO, for reasons of both healthy development and safety, we advise that you do not let your babies sleep in car capsules when they are not in the car, but rather, to be transferred out of the car seat and into their bed, or another form of carrier, such as a pram or your arms. This also applies to any device that puts a baby in this position, such as bouncinettes and rockers.
Developmentally, the postural challenges the semi-curled position creates to the back and neck, as well as the prolonged flexed position, prevents a baby from stretching out fully into the extended position. Extension of the muscles is important to develop healthy muscle tone and enables the inhibition of a reflex that allows babies to learn to move forward on their tummies, a very important milestone.
From a safety point of view, several research studies (1) now confirm that this curled position leads to decreased oxygen levels, which can hamper healthy brain function and can also, tragically, result in death from positional asphyxiation. Researchers from Auckland University and the Cot Death Association (2, 3) warn that babies’ time in car safety seats should be kept to a minimum, after the findings in their long-running research.
The researchers have previously shown a reduction in mild breathing problems in babies whose car safety seat was fitted with a simple foam insert with a slot for the back of the head. Babies’ heads are larger, relative to the body, than adults’ heads, and protrude behind the line of the back. The commercially available insert helps to keep the baby’s body forward. It also allows the head to remain upright even when the infant is asleep, rather than slumping forward, which can obstruct breathing when the chin is on the chest and pushed back.
A larger study, published in Pediatrics in July 2013, confirms that using the insert does reduce breathing risks for babies, who were on average eight days old, but it does not eliminate the seats’ risks.
Comparing sleep studies in two groups, 39 babies in each group, the researchers found those whose car safety seats had the inserts had fewer instances of stopping breathing because of a blocked airway and had less severe reductions in oxygen saturation levels than the non-insert group. However, both groups recorded reduced oxygen levels in the blood. This means that less oxygen gets to the brain, and over long periods of time, this can make a difference in how well the brain can function.
“There is now compelling evidence that hypoxia (oxygen deficiency to the brain) is associated with behavioural problems and adverse effects on development and school performance,” Dr McIntosh said (3).
This study also highlights the importance of not using car seats as a place of sleep for infants. The Cot Death Association confirms that “car seat use has been associated with apparent life-threatening events and with at least some otherwise unexplained sudden deaths in term infants.”
In their journal paper, the researchers note car safety seats are essential for infants’ safe transport in cars. Still, they express concern at the reported high rates of infants spending more than 30 minutes daily in a car seat, “often for sleep out of the car as well as for transport”. The research team strongly advise that car seats should not be used for infant sleep outside the car. Car seat use should be restricted to the minimum time required for travel.
Dr Jane Williams (PhD, BMgt, RN(Paeds)) is a Director of GymbaROO-KindyROO and is one of Australia’s leading experts on baby and child development.
Dr Tessa Grigg (PhD, Dip Tch Primary and ECE) is an experienced teacher and the Research and Education Manager at GymbaROO-KindyROO.
Bindy Cummings (B.Ed hons) is a teacher, a GymbaROO early childhood neuro-developmental consultant and the co-creator of GymbaROO’s Active Babies Smart Kids series. She has been writing articles for GymbaROO’s First Steps magazine, digital platforms and media for over fifteen years.
- Kornhauser Cerar L, Scirica CV, Gantar IŠ, Osredkar D, Neubauer D, Kinane TB. A comparison of respiratory patterns in healthy term infants placed in car safety seats and beds. Pediatrics. 2009;124(3):981-2.
- Tonkin SL, Vogel SA, Bennet L, Gunn AJ. Apparently life threatening events in infant car safety seats. BMJ: British Medical Journal (International Edition). 2006;333(7580):1205-6.
- McIntosh CG, Tonkin SL, Gunn AJ. Randomized Controlled Trial of a Car Safety Seat Insert to Reduce Hypoxia in Term Infants. Pediatrics. 2013;132(2):326-31.