Hospitals are more likely to test Black pregnant people for substance use compared with pregnant people who are white, a new study finds. Researchers said the difference is due to racial bias, The New York Times reports.

The study analyzed medical records of 37,860 patients who delivered a baby at a large Pennsylvania health care system between 2018 and 2021. Black patients, regardless of whether they had a history of substance use, had a greater probability of receiving a urine toxicology test at delivery compared with white patients and other racial groups. However, Black patients did not have a higher probability of a positive test result than other racial groups.

“Any given clinician may not be thinking about bias, but when you look at these kinds of data, you can see there is no other explanation,” said researcher Marian Jarlenski of the University of Pittsburgh School of Public Health.