Pregnancy and child

Warning over car seats for babies

“Parents should keep children in rear facing car seats ‘until the age of four’,” The Daily Telegraph has reported. It said that this would give greater protection in a car crash. According to the newspaper, while parents are currently advised to place babies and young children in rear-facing seats, most children grow out of them by the time they reach around eight months old (about 9kg in weight), at which point it is common to switch children to front-facing seats.

This news report was based on a review of the current body of research on the safety of children’s car seats. The research that was examined, which included crash data on children and crash test dummies, suggests that children are less likely to suffer severe crash injuries when sitting in a rear-facing seat than in a front-facing seat. One particular research article reviewed estimated that children were around 75% less likely to suffer severe injuries in rear-facing seats.

These findings must be interpreted in light of the absolute number of children seriously or fatally injured in car accidents, which in 2007 was around 3,000 in Great Britain. Any proposal to help prevent the injury or death of children will be of major interest to both parents and clinicians and this review will undoubtedly lead to important debates on the subject.

Where did the story come from?

This research was carried out by Dr Elizabeth Watson and Michael Monteiro, clinicians working at Sunny Meed Surgery in Woking and the Royal Surrey County Hospital in Guildford. The study does not appear to have had any external funding and was published in the British Medical Journal.

What kind of scientific study was this?

This was a review of research that directly compared rear-facing and forward-facing car seats. The authors say that the use of appropriate restraints “significantly reduces morbidity and mortality” in children but that many babies are switched from rear-facing to forward-facing seats once they weigh 9kg.

This review was featured in a section of the British Medical Journal called Change Page, which alerts clinicians to the immediate need for changes in practice and ensures that these changes are aligned with current evidence.

The authors did not discuss their methods in great detail but said that they searched for literature in the Scopus database, a very large repository of studies and research. They searched using the specific terms “rear-facing child safety seat” and “forward-facing child safety seat” and prioritised studies that directly compared the two or that discussed advantages or disadvantages of either seat type. They also looked at the reference lists of these studies and searched child care safety websites for further relevant published research.

Using the evidence that they gathered, the authors discussed studies that examined the effects of accidents on children while in front- and rear-facing seats. In this discussion, they referred to studies that show the spine is at risk in a forward-facing car seat and that in rear-facing seats the head, neck and spine are kept fully aligned and crash forces are distributed more evenly across the body.

The authors discussed the practice of using rear-facing seats in Sweden, citing prevalence studies on the use of different types of seats and a study based on Volvo’s insurance company records of accidents from 1976 to 1996, which suggest rear-facing seats are safer. Crash test and numerical simulations were drawn on to further support these arguments.

The authors also looked at what they considered to be the barriers to changes in practice and made recommendations as to how healthcare professionals could implement changes. 

What were the results of the study?

The authors particularly discussed a retrospective cohort study that analysed vehicle crash data from 1998 to 2003 to examine the severity of injuries in children under two years old. This research compared accidents that happened while children were in rear-facing seats (352 children) and forward-facing seats (518 children). This study found that those in forward-facing seats were 1.76 times more likely to be seriously injured than those in rear-facing seats. The authors describe this research as “pivotal”, and cite crash test and numerical simulations which support a lower injury risk from using rear-facing seats.

The researchers say that this difference is due to children’s spinal anatomy and “the relatively large head mass” that children have. They believe this can lead to excessive stretching or even tearing of the spinal cord if a child is involved in a frontal (head-on) crash while in a forward-facing car seat. In rear-facing car seats, the head, neck and spine are kept fully aligned and crash forces are dispersed across all these body areas.

The researchers say that many parents and healthcare professionals may not be aware that it is safer to leave children in rear-facing seats for as long as possible and that the cost of buying rear-facing seats, many of which are more expensive that forward-facing ones, may be prohibitive. They also believe that healthcare professionals should advise parents that rear-facing seats are safer than forward-facing seats for children under four years old and that seats must be properly installed by a trained individual, such as a vendor or road safety officer. They also call for clearer labelling by manufacturers.

What interpretations did the researchers draw from these results?

The clinicians conclude that rear-facing seats are safer than forward-facing seats for children under four years old and that parents and guardians should be advised to keep young children in rear-facing seats for as long as possible.

What does the NHS Knowledge Service make of this study?

According to official Department for Transport figures, collision-related deaths and serious injuries in children have steadily fallen since the 1980s, but 3,000 children under the age of 15 were killed or seriously injured in Great Britain in 2007. This is 3,000 incidents too many and any viable proposal to prevent the injury and death of children will be of major interest. Consideration of the type of seat that toddlers use may go some way towards reducing injuries in children involved in traffic accidents.

This literature review appears to have been performed with a systematic approach and, although the article does not feature sufficient detail to fully critique their methods, it appears that that authors have made an effort to find and analyse all published research in this field and not just those studies that support their theories.

Overall, the research that the authors discuss suggests that children are less likely to suffer severe injuries when sitting in a rear-facing seat compared with a front-facing seat. The body of research assessed includes reviews of both crash data on children and crash test dummies.

This is important research and will no doubt stimulate discussion of a major child-safety issue, which is of great interest to both parents and clinicians. The evidence produced to date suggests that rear-facing seats are safer than front-facing ones and that parents should be encouraged to keep their children in rear-facing seats for as long as possible.

NHS Attribution