A new study finds little evidence that mothers’ use of cocaine during pregnancy in the 1980s led to a proliferation of “crack babies,” the Associated Press reports.

Researchers reviewed 27 studies that included a total of 5,000 11- to 17-year-olds, whose mothers used cocaine during pregnancy. The teens came from low-income families, most of which were black and urban. Some of the studies found a mother’s cocaine use could increase the risk her child would have behavior and attention problems, anxiety and worse performance in school. These effects generally were small, and could have been caused by other factors, such as family problems and exposure to violence, the researchers report in the journal Pediatrics.

In the 1980s, when use of crack cocaine was widespread, some babies born to women using the drug were jittery and had smaller heads, the article notes. At the time, studies concluded maternal crack use could lead to irreversible brain damage in children. Many of these children were born prematurely, which could have caused many of their symptoms, the researchers said. Studies that followed these children beyond infancy did not find severe outcomes.

“The field of prenatal cocaine exposure has advanced significantly since the misleading ‘crack baby’ scare of the 1980s,” the study authors wrote.