(CNN) Every hour, two children 5 or younger are treated in emergency rooms for injuries related to strollers or car carriers, according to researchers.

Nearly 361,000 toddlers were treated in hospitals for injuries caused by falls or tip-overs during the 21-year period ending in 2010, according to a new study published Wednesday in the journal Academic Pediatrics

Most often, children suffered head injuries (nearly 62% of the total incidents) and face injuries (nearly 25%).

"I'm a mom. I have two young children, and I use strollers and carriers to transport my children around," said Kristin Roberts, author of the study and a research associate in the Center for Injury Research and Policy at Nationwide Children's Hospital in Columbus, Ohio. "We expect strollers and carriers to be safe and provide a secure way to transport children."

Increasing number of concussions and traumatic brain injuries

Even if most of the injuries are simple bumps and bruises, others can be serious, Roberts said.

She and her colleagues used data gathered from the National Electronic Injury Surveillance System. This database, which is operated by the U.S. Consumer Product Safety Commission , tracks injuries related to sports, recreation and consumer products that have been treated in emergency rooms across the country.

Roberts and her colleagues searched the database for children age 5 or younger who sustained an injury during an accident involving a stroller or carrier between the years 1990 and 2010. A total of 360,937 children were treated in emergency rooms for these kinds of accidents, an average of 17,187 each year, the research team discovered.

For stroller-related accidents, slightly more than half the patients were male, and 42% were younger than 12 months. Nearly 40% of the patients were diagnosed with a soft-tissue injury such as a bruise. However, almost a quarter were diagnosed with traumatic brain injury/concussion.

"A concussion is considered to be a mild brain injury," said Courtney N. Lenard, a spokeswoman at the National Center for Injury Prevention and Control , explaining that most children recover quickly from a mild brain injury. Still, at a young age, even a mild brain injury can harm a child's development, learning and behavior.

"Concussions may have long-term consequences when they occur in young children," Roberts said.

The proportion of carrier-related brain injuries/concussions tripled from about 17% in 1990 to roughly 53% in 2010. "We're not sure why this increase occurred. Perhaps this is due to greater awareness of concussions," she suggested.

For carrier-related accidents, slightly more than half the patients were boys, and the overwhelming majority -- 89% -- were less than a year old. While soft-tissue injuries accounted for 48% of these injuries, traumatic brain injury/concussion accounted for nearly 35%.

Nearly 7% of children injured in a carrier accident and slightly more than 2% injured by a stroller had to be hospitalized.

Roberts noted that she and her colleagues looked only at injuries treated by hospital emergency rooms. Children cared for at home or by a private practice or clinic were not included, so the study is actually an underestimate of the total number of injuries that occurred over two decades, she said.

New mandatory guidelines

"The good news for parents who rely on strollers and carriers is that new federal mandatory safety standards for these products address many of the risks to children identified in this study," said Elliot Kaye, chairman of the U.S. Consumer Product Safety Commission. Though the researchers used information collected by the commission, neither Kaye nor the commission was directly involved in the study.

"Newer is better," Kaye added, explaining how all newly manufactured strollers are required, as of September 2015, to meet mandatory standards which address common injuries. Kaye said the products meeting the safety guidelines and designed with critical security features are in stores and online today. Children should always be properly clipped or buckled in to prevent falls that can cause serious injuries, he added.

Debra Holtzman, author of " The Safe Baby ," echoed Kaye's advice and recommended that parents read reviews and do online research before purchasing products, as well as checking for incidence reports at saferproducts.gov

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"Make sure your stroller is appropriate for your child's size," said Holtzman, who also says it's necessary to read and follow manufacturer's instructions on assembly, care and use. Naturally, adult supervision is required, and children should never remain unattended in a stroller.

"When using a carrier, we encourage parents to keep the carrier low to the ground," said Roberts. If an accident occurs, the child has less distance to fall, she explained. "And don't allow children to climb into the stroller by themselves, because this is how it tips."