Ontario Mothers' Substance-Related ER Visits Rose 5% a Year

Emergency department visits for substance use among Ontario mothers with dependent children grew almost 5 percent a year between 2008 and 2024, more than double the rate among women without children, according to a study published October 26 in the Canadian Medical Association Journal. Among mothers under 25, the annual increase ran at roughly 8 percent, about four times the comparison group.

The analysis drew on ICES health administrative data covering 988,106 birthing parents matched by age to 1,198,063 other women — 2.2 million people in all, one of the largest samples yet assembled on substance use among parents.

A gap in a field that studies everyone else

Parenting status is not a variable most substance use research carries. "Growing up with a parent who has a substance use disorder is considered an adverse childhood experience, which can increase a child's risks of poor health, developmental challenges, and future substance use," said Dr. Colleen Webber, an investigator at Bruyère Health Research Institute in Ottawa and the study's lead author. "Despite this, there is surprisingly little evidence on substance use in parents, although many studies have been conducted on the general population."

The researchers asked a narrower question than whether substance use rose in Ontario overall. They asked whether mothers were being spared a trend that has reshaped emergency care across North America. "We talk a lot about the opioid and toxic drug crises, and much of the focus has been on overdoses and deaths," said coauthor Dr. Daniel Myran, a scientist with the University of Toronto's department of family and community medicine and ICES. "We asked whether mothers have been spared these overlapping crises, and the answer appears to be no. Substance harms have risen in moms at least as much as in females who do not have children."

Hospital admissions tell the same story

Emergency visits are the more sensitive indicator, but the inpatient numbers moved in the same direction. Substance-related hospital admissions among birthing parents rose from 99 to 259 per 100,000 person-years over the study period. Among women without children, the rate went from 136 to 209 per 100,000 person-years. Mothers started lower and finished higher, which is the part of the chart the authors did not expect.

The growth was not evenly paced. From 2014 to 2018, substance-related emergency visits for mothers climbed about 11 percent a year. After that the rate of increase fell back to roughly 2 percent annually — still rising, but at a slope close to the comparison group's.

Alcohol remains the leading cause, by a wide margin

Relative increases were steepest for amphetamines, cannabis and opioids, and it would be easy to read the study as an opioid story. The absolute numbers say otherwise. Alcohol accounted for 46 percent of substance-related emergency visits and 41 percent of substance-related hospitalizations among mothers in 2024.

"That may reflect the 'pinking' of alcohol, where products are being specifically marketed to women and to moms through 'mommy wine culture,'" Webber said. The finding complicates a treatment landscape where opioid-specific funding, naloxone distribution and medication for opioid use disorder dominate the policy conversation, and where alcohol withdrawal — the one substance in this list that can kill a patient during unsupervised detox — is handled by a smaller set of detoxification and alcohol treatment providers.

The youngest mothers are driving the trend

The divergence by age is the study's sharpest result. Rates for mothers under 25 rose more than four times faster than for other women, a pattern the authors attribute to circumstances surrounding early parenthood rather than to parenthood itself. The study does not examine whether motherhood or parenting causes substance use, and the researchers say so explicitly: the higher rates in young mothers likely relate to factors that also make early childbearing more likely, including income, housing instability and exposure to intimate partner violence.

Myran described the implications as running in two directions at once — to the mother's own care, and to the children she is usually the one caring for. "Previous studies have found that many children in the United States have lost a parent to an overdose," he said. "But living with a parent who has a substance use disorder can have very negative impacts on a child, and this has not received much focus. Our study suggests an increasing number of children in Ontario may be growing up with a mother who has a serious substance use disorder."

Rare in absolute terms, common enough to matter

Substance-related emergency visits and hospitalizations remain unusual events for mothers, affecting around 0.5 percent. Myran cautioned against reading that number as reassurance. "For each mother seeking care in these settings there are multiple others who did not seek care either because of stigma or because their substance use was not severe enough to need hospital care," he said.

The policy recommendations in the paper are structural rather than pharmacological: integrate substance use and mental health services in one setting, design schedules around childcare, and address the upstream conditions — income support, housing, violence prevention — that the authors treat as part of the clinical picture.

What the data cannot show

Ontario's administrative records identify diagnoses and service use, not severity, intent or outcome. The study covers one Canadian province, and its authors note that parenting status was inferred from birth records and dependent children in the household, which misses parents whose children are not captured in that data. It also cannot separate a genuine increase in substance use from a rise in help-seeking, though a simultaneous rise in hospital admissions — which are harder to obtain than an emergency visit — argues against help-seeking alone as the explanation.

The study lands in the same month that a U.S. nonprofit documented 902 criminal cases against pregnant women since the Dobbs decision, most involving allegations of drug or alcohol use. Both findings point at the same population from opposite directions: one measures mothers arriving at hospital doors, the other measures what happens to them when they do. People seeking help for alcohol or drug use can call the SAMHSA National Helpline at 1-800-662-4357, and substance use disorder treatment options are searchable by location.