Last April, Maryland resident Elizabeth Eden went to St. Joseph Medical Center to give birth to her daughter. With no labor complications and a healthy baby welcomed into the world, the day should have been one of joy and celebration. Yet thanks to a well-documented but often overlooked clinical phenomenon, the experience took a stressful turn.

"I was in labor. I was sitting in the bed. I was having contractions. I was on a Pitocin drip, and the doctor came in and said, 'You've tested positive for opiates,'" Eden told local news station WBAL-TV.

Recalling a long-ago lesson in health class – one that many of us have heard but likely paid little thought to since – Eden realized why this had happened.

"I said, 'Well, can you test me again? And I ate a poppy seed bagel this morning for breakfast,' and she said, 'No, you've been reported to the state,'" Eden continued.

Routine drug screening of both mothers and newborns has become increasingly common in the face of the raging opioid abuse epidemic. In this case, St. Joseph Medical Center analyzed a urine sample from Eden and concluded she had been exposed to opiates based on the detection of greater than 300 nanograms of drug per milliliter of liquid (ng/mL). Dr Judith Rossiter-Pratt, chief of the hospital’s OB-GYN department, told the station that their standard tests use this relatively low threshold because it allows them to detect more users.

However, research conducted over the past several decades has proven that eating just one poppy seed-laden bagel or several rolls can introduce enough opiates into the body that tests performed hours to several days after consumption will register hundreds of ng per mL of urine. The seed pods of the poppy plant, Papaver somniferum, are the source of opium – a milky fluid produced to defend the flower against grazing animals that contains a number of psychoactive compounds, including morphine, codeine, and thebaine: the molecule that forms the basis of synthetic opiates, aka opioids.

While there are no opiates within the seeds, they are covered in these compounds. According to a clinical education column by Quest Diagnostics, a nationwide medical testing company, the amount of opiates that we ingest in food products varies between poppy harvests and the amount of washing that the seeds undergo during processing.

For these reasons, eating certain batches of poppy-seeded foods or those that contain a lot of seeds can have serious repercussions for anyone who is undergoing chemical monitoring. Indeed, events similar to Eden’s became so common that federally regulated workplace testing programs raised their morphine cutoff from 300 ng/mL to 2,000 ng/mL in 1998 in order to lower the number of false positives from food, though Quest notes that even this number is not high enough to prevent all instances – after all, innocent and delicious poppy seed cakes have been shown to induce thousands of ng/mL of morphine in urine.

After the failed drug test, Elizabeth Eden was not allowed to bring home her daughter home until a state-assigned social worker evaluated her and searched the home for signs of drug misuse. Although she was cleared in five days, she describes the experience as traumatizing.