Children whose families are affected by the opioid epidemic face unique challenges, including having to monitor parents for overdoses, according to a new report.

The report finds a dramatic increase in the number of children in foster care since the opioid epidemic began. By 2017, about 440,000 children were in foster care. An additional 2.7 million children are estimated to be living with family members such as grandparents, aunts and uncles, or older siblings.

The report, The Ripple Effect: The Impact of the Opioid Epidemic on Children and Families, was written by the United Hospital Fund (UHF).

“Children in families affected by substance use are often hidden from view until there is an overdose, arrest, or other crisis,” Carol Levine, co-author of the report and Director of UHF’s Families and Health Care Project, said in a news release. “The good news is that existing capabilities in agencies and programs that support children and families can be leveraged, along with lessons from prior public health crises—the HIV/AIDS and crack cocaine epidemics in particular.”