BERLIN (AP) — German authorities have closed three pharmacies in the western city of Cologne after a pregnant woman died after using a tainted diabetes test.

North Rhine-Westphalia's state Health Ministry said Thursday the pharmacy that dispensed the glucose screening test and two of its branches had been shut down as a precaution as authorities investigate how the preparation became poisonous, the dpa news agency reported.

Prosecutors say an autopsy showed the 28-year-old woman died from multiple organ failure after using the test last week. Her unborn child also didn't survive despite efforts to save it through an emergency cesarean section.

Prosecutors say they are investigating whether negligence led to the contamination or whether the test was intentionally tampered with.