For thousands of parents in the U.S. every year, one of the best and worst days of their lives begins at the same place and time: in the hospital, when their babies are born. As they share the joy of bonding with their newborns, doctors tell them they have just tested positive for drugs — but the tests are wrong.

Hospitals across the country routinely drug test people coming in to give birth, using pee-in-a-cup tests that are notoriously imprecise. People who have eaten poppy-seed bagels or taken over-the-counter heartburn or cold medications can test positive for meth or opiates. As a result, many face child protective services investigations, and some even lose custody of their children.

The Marshall Project’s reporter Shoshana Walter, in collaboration with CBS Sunday Morning correspondent Erin Moriarty and producer Sari Aviv, investigated how hospitals nationwide are reporting parents to child welfare services over inaccurate drug test results. In many cases, the hospitals themselves gave patients medications during labor, then reported them for testing positive for those same substances.

Watch the CBS Sunday Morning investigation above and read our investigative series.