WASHINGTON — The House of Representatives on Wednesday unanimously passed legislation to improve safety planning for children who are born dependent on opioid drugs.

A similar bill is pending in the Senate. It is one of more than a dozen new measures that are aimed at addressing a national epidemic of addiction to pain pills and cheap heroin.

The legislation came in response to a Reuters investigation last year titled “Helpless and Hooked,” which revealed that at least 110 babies had died since 2010 after being born dependent or exposed to opioids and sent home with parents ill-prepared to care for them.

“It’s hard to imagine that stories like these could be any more tragic,” Rep. Lou Barletta, a Pennsylvania Republican who is the prime sponsor of the bill, said on the House floor. “Unfortunately, they are. Because they should have and in many cases could have been prevented.”

Only nine of the 50 states followed a federal law requiring them to track and help those newborns, Reuters reported. The news agency found that more than 130,000 newborns were diagnosed with drug withdrawal over the last decade, but most of them weren’t reported to state child-protection authorities.

In April, the U.S. Department of Health and Human Services asked all states to report by June 30 whether and how they are following the existing law, known as the Child Abuse Prevention and Treatment Act. States receive federal funding after giving assurance they are complying.

Rep. Katherine Clark of Massachusetts, the leading Democratic co-sponsor, emphasized that the new legislation would require help for not only the newborn but also for the mother and family. That provision is aimed at overcoming resistance to reporting cases of newborn addiction among doctors and other health care workers, who sometimes fear that mothers may be punished if the cases come to official attention.

“This important step with this bill is to ensure that the whole family is healthy and successful and supported,” Clark said. The measure, formally known the Improving Safe Care for the Prevention of Infant Abuse and Neglect Act, passed 421-0.

Children’s advocates are seeking more federal funding to go with the commitment. “We would view this as a good first step, but they need to make it real and put some money in it,” said John Sciamanna, vice president of public policy for the Child Welfare League of America.

Among the other opioid-related bills adopted by the House on Wednesday was one designed to help states emulate a pilot program for drug-affected newborns in Huntington, West Virginia. Rep. Evan Jenkins, a Republican who helped create the Huntington facility, known as Lily’s Place, before he became a congressman, said his bill would help improve access to care for poor babies and women on Medicare.