A simple technique may help determine whether a baby was exposed to cocaine during pregnancy: Listen to her cry. It can be tough to diagnose babies with cocaine-linked health issues that may not appear until they're older, Medical Daily reports.

But a baby who seems healthy may reveal through her cry that her nervous system has been affected by the drug, researchers at the University of North Carolina say via Eureka Alert.

In their study, researchers found that the cries of both human infants and rat pups contain similar characteristics associated with a mother's prenatal cocaine use. The study focused on a high-pitched sound called hyperphonation, which is comparable in babies and rat pups exposed to the drug.

The findings are helpful, says the study's lead author, because it can be difficult to tell whether nervous system damage is related specifically to cocaine or to other factors.

The link to rat pup vocalizations will allow assessments "that can be used to detect the isolated effects of cocaine or similar drugs on brain limbic mechanisms common to humans, rodents, and other mammals," the lead researcher says.

Maternal cocaine use can lead to problems with babies' brains, genitals, and kidneys, and they can experience withdrawal symptoms from the drug—though a recent study suggested exposure to crack may not be as dangerous as was thought.

This article originally appeared on Newser: Baby's Cry May Reveal Cocaine Use by Mom

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