Once a month, Kim Hudson, 51, knocks on the door of her own home in Warren, Michigan.

Eleven-year-old Ava answers the door and Hudson gets to “play grandma for the day.”

On the surface, this ritual isn’t that unusual. Hudson is actually Ava’s grandmother.

But ever since Ava’s mother, Katelin, died from a heroin overdose three years ago, Hudson has had a much larger role.

“I was robbed of being a grandma,” Hudson told Healthline. “Now I’m the full-time parent. I never really got to play the grandma role.”

Hudson never expected her daughter — who had Ava when she was 17 and was a “good mom” — to struggle with opioid addiction.

But after Katelin had her wisdom teeth pulled when she was 21, everything changed.

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“They gave her some strong pain killers, and after that her life just unraveled,” said Hudson.

Katelin was in and out of rehab. When she started using heroin, she was in and out of jail.

While Katelin was in jail in 2011, Hudson and her husband — who has since passed away — applied for temporary full guardianship of their granddaughter.

They did it for one simple reason — Ava.

“My intention was never to take away Katelin’s role as a parent,” said Hudson, “but I had to protect that little girl.”

As the opioid epidemic forces more children out of their parents’ custody, grandparents like Hudson are stepping in to fill the gap.

But as they become the primary caregiver for their grandchild — or grandchildren, in some cases — older adults are seeing their lives turned upside down.

“They thought this was a time they were going to get to go to the movies and play cards with their friends. Instead, they are being a full-time parent,” Jaia Peterson Lent of Generations United, a Washington-D.C.-based nonprofit, told Healthline.

Grandparents who do the right thing also face many obstacles.

These range from navigating child welfare systems to caring for grandchildren that may have special medical or therapy needs — all while dealing with the effects of their own child’s addiction.

Grandparents face many challenges

After years of decline, the number of children in foster care is once again on the rise, reports Generations United.

There were more than 415,000 children in foster care in 2014, up from about 398,000 in 2011.

Experts point to the opioid epidemic.

Children may be removed from their home when their parents are jailed or forced into treatment due to opioid use, or when the parents die from an opioid overdose.

In 2014, more than 40 percent of children in foster care with relatives were there because of their parents’ opioid, alcohol, or other drug use, according to Generations United.

Dr. Lawrence S. Brown, Jr., chief executive officer of START Treatment & Recovery Centers in Brooklyn, New York, told Healthline that he has “seen an increasing number of patients bringing their children or grandchildren to our treatment programs while they are receiving their treatment. We believe that has a lot to do with the opiate epidemic.”

These are people who are trying to get clean so they can maintain custody of their child or grandchild.

But Brown said that START has also seen a jump in requests from children and family services about whether people in treatment are still able to take care of their child.

When addiction treatment — whether it is medication-assisted treatment or individual or group counseling — doesn’t work, foster care may be the next step.

States hardest hit by the opioid crisis have seen dramatic increases in foster care.

In Ohio, drug overdose deaths rose 21 percent between 2014 and 2015, according to the Centers for Disease Control and Prevention (CDC).

Since 2010, the number of Ohio children placed with relatives in foster care has risen 62 percent, according to Generations United.

Overall, about 2.6 million American children are being raised by grandparents or other relatives, according to the nonprofit.

Often without enough help.

“There is a real need for more supports and services, and also more information about the existing supports and services that are available to grandparents and other relatives,” said Peterson Lent.

Many grandparents expected they would be enjoying the freedom of retirement, not raising another child.

“They were not planning for this,” said Peterson Lent. “They may have gotten a call in the middle of the night saying ‘Take this child or they’re going to end up in foster care.’”

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The financial burden is overwhelming for many grandparents.

There are the routine costs of daycare, clothing, and food. But there are also adoption and legal fees.

“I had to get a lawyer and I had to file court papers,” said Hudson. “I had to pay money to get full custody, which was silly, because I was getting full custody of my own grandchild.”

Children who witnessed their parents’ substance abuse, or who were exposed to opioids before birth, may also need ongoing medical care and therapy in order to live healthy lives.

Some grandparents raising grandchildren are also living on a fixed income. And nearly one in five live below the poverty line, according to Generations United.

Older adults may even be dealing with their own health issues. This can make it hard to keep up with the go-go-go pace of a child. Some grandparents may even forgo their own medical care.

“We find that often the children are the priority,” said Peterson Lent. “If the grandparent has a doctor’s appointment but something comes up with the child, they’re often going to neglect their own health needs and prioritize the needs of the children.”

They may even cut back on their medication in order to put food on the table or pay for other necessities for their grandchild.

Not enough support for grandfamilies

Some resources and financial assistance are available to grandparents who step in. These vary from state to state and depend on many factors, including their income and whether they are a licensed foster care parent.

The monthly stipends for fostering can help.

But according to Generations United, for every child in foster care with relatives, there are 20 children being raised by relatives outside the foster care system.

“That means that they are going to have access to much less support and services — and certainly less financial support — than if they become a licensed foster parent,” said Peterson Lent.

Ironically, when grandparents step in before their grandchild ends up in the foster care system, they are missing out on support that can help them take care of the child.

Hudson was one of those grandparents.

“I never went the foster care route at all, because my husband was here and we were providing for her,” she said.

But now that her husband is gone, she wonders if she could have gotten more support.

“But it’s always worked up to this point,” she added. “And it’s still working. I make it work.”

Her older children — age 25, 21 and 20 — all moved back home, which helps.

“We split the household into four,” said Hudson, “and we all take care of each other — and Ava.”

But even for grandparents who are registered foster parents, the small monthly stipend they receive from the foster care system may not cover the added legal and medical expenses.

And in some states, if they adopt their grandchild, the financial support dries up.

Hudson and her husband did apply for legal guardianship of their granddaughter. Without this formality, grandparents would have a hard time doing things like enrolling their grandchildren in school or taking them to the doctor.

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Experts say that there are good reasons for providing more support for grandparents and other relatives to take in these children.

“The research is really pretty clear that you should prioritize relatives for children when you can,” said Peterson Lent “Children do better with relatives, compared to nonrelatives, when we have an appropriate relative to place them with.”

There are other benefits, as well.

“Those relatives who step in to care for the children, and keep them out of the formal foster care system, they’re not only doing the right thing for kids — by reducing trauma and keeping them with family,” said Peterson Lent. “They’re also saving taxpayers $4 billion each year by keeping kids out of foster care.”

Already, state foster care budgets are stretched thin, social workers are overloaded, and there is a shortage of families willing to provide temporary homes for children.

Relatives play an important role in helping children left behind by the opioid epidemic — and in helping an overburdened foster care system.

“As we see the uptick in foster care placements with the opioid epidemic,” said Peterson Lent, “we’re also seeing child welfare systems increasingly rely on relatives to meet that increasing need.”

Generations United reports that, in 2014, more than a third of all children who were removed from their home because of drug or alcohol use were placed with relatives.

Some progress in helping grandparents

The opioid epidemic is not the first time that grandparents and other relatives have had to step up to take of children affected by their parent’s drug addiction.

But some progress to the system has been made since the crack epidemic in the 1980s and 1990s, or the earlier opioid epidemic in the 1970s.

One step forward is The Fostering Connections to Success and Increasing Adoptions Act of 2008, which promoted placement of children with relatives. This includes giving relatives financial support similar to what other foster parents receive.

“As a result of that law, we are seeing that relatives are also being identified and reached out to more regularly,” said Peterson Lent. “Not every child welfare agency is doing that in the way that they should be, but we’ve certainly seen progress.”

Peterson Lent added that one thing the child welfare system doesn’t do well is provide earlier support for families, so foster care isn’t the only option.

“We need to turn child welfare financing on its head so that states can use some dollars for proven programs that help prevent that tragedy, that help prevent a need for children to enter foster care,” said Peterson Lent.

Brown said there is also a need for more support for the children of parents with an opioid addiction, to keep them from ending up on the same path.

Although there is a lack of real data, said Brown, “what we are seeing is an increase in generational addiction.”

This is why START developed a program, called Teen START, which focuses on helping adolescents stay clear of the cycle of drug addiction.

Like many other grandparents caring for their grandchildren, Hudson turned to a support group — in her case, the Grandparent2Grandparent Facebook group.

She is thankful that she has not had to deal with as many “horror stories” as other parents.

She is also thankful for her unexpected life with Ava, her fifth “child.”

“She is my hero and my rock,” said Hudson. “She’s very upbeat and positive.”

“Does she miss her mom? Yes, she misses her mom,” she added. “But I don’t think she misses the situation that she was in.”

This article first appeared on HealthLine.com.