A U.S. House committee is launching an inquiry into the federal government’s enforcement of a law designed to protect drug-dependent newborns.

The inquiry, launched by Representative John Kline of Minnesota, is in response to a Reuters investigation that found 110 cases of babies and toddlers whose mothers used opioids during pregnancy, and later died preventable deaths.

In each case, the babies recovered enough to be discharged from the hospital, but were sent home to families not equipped to care for them.

The number of babies treated for the drug-withdrawal syndrome known as neonatal abstinence syndrome (NAS) has almost quadrupled in the last decade, according to a last year.

Babies born with NAS undergo withdrawal from the addictive drugs their mothers took during pregnancy, such as oxycodone, morphine or hydrocodone. NAS affected seven babies for every 1,000 admitted to a neonatal intensive care unit in 2004. That number jumped to 27 infants per 1,000 by 2013.

Reuters found that no more than nine states comply with a 2003 law that calls on hospitals to alert social workers whenever a baby is born dependent on drugs.

Kline chairs the House Education and the Workforce Committee, NBC News reports.

Two U.S. senators have also asked the federal government to address the growing problem of drug-dependent newborns. They say thousands of infants are born each year to mothers who used opioids during pregnancy.

Senator Robert Casey of Pennsylvania called for hearings on why a federal law that directs states to protect drug-dependent newborns is not being enforced. Senator Charles Schumer of New York wants the Obama Administration to increase funding to help drug-dependent babies.