While experts said more research is needed on the subject, they emphasized that this new finding reinforces the urgent need to identify and treat depression among pregnant women -- not just for their sake, but potentially for the sake of their child as well.
"It's definitely been proven that there's genetic linkage for psychiatric disorders," Dr. Gabrielle Shapiro, a child psychiatrist from the American Psychiatric Association, told ABC News. "And identifying [depression] in early childhood would be the best way to have an impact on ... lifetime trajectory functioning" for children with mental illness.
In the study, researchers in the U.K. reviewed survey data from a large database of women who gave birth during the early 1990s. They focused on a subset of over 5,000 mothers and assessed their reported symptoms of depression, both during pregnancy and after they gave birth.
The children were also surveyed throughout childhood and young adulthood. Researchers found that children of depressed mothers not only had more symptoms of depression themselves but also that the symptoms escalated faster in them than they did in children without exposure to maternal depression.
"We found that the depression scores of offspring of mothers ... increased at a greater rate over time -- in other words, their scores went up by more points each year than offspring of non-depressed mothers," Dr. Rebecca Pearson, co-author of the study, told ABC News.
The data also revealed a potential association between a father's depression and childhood depression, though the study was not constructed to assess that relationship fully.
In a press release, Dr. Joanne Black, chair of the Faculty of Perinatal Psychiatry at the Royal College of Psychiatrists, said the study "shows that the timing of depression in parents (during pregnancy, after childbirth or both) and if the mother, father or both were affected, are all important risk factors for the child's future mental health."
Exactly why this timing appears to be important is still unknown, but may point to the importance of screening for depression during the peripartum period and supporting mothers with mental health conditions. It also begs the question: Are genetic factors that lead to depression passed from mother to child in the womb?
Although the findings are intriguing, it remains unclear if the results are applicable to the population at large, as this study was conducted in a part of the U.K. with little socioeconomic or racial diversity.
This matters to Shapiro, who stressed the importance of recognizing racial disparities in childhood mental health.
"It's even more important to screen our [Black, indigenous, people of color] population and make it more acceptable for them to have early intervention and be OK with treatment discussions," she said.
Moving forward, the study's findings may help health care providers identify and treat children through supporting families with mental health needs.
Ronnye Rutledge is an internal medicine and pediatrics resident from Boston, and a contributor to the ABC News Medical Unit.