While prenatal drug exposure can lead to various complications for infants, diagnosing certain health defects that may not show up until later in life can be problematic, since the baby’s initial development is considered normal. A recent study conducted at the University of North Carolina School of Medicine has revealed an acoustic characteristic in the sound a baby makes while crying that could be used to identify complications of the nervous system caused by prenatal cocaine exposure.

"These findings are important because studies of prenatal drug exposure in humans are always limited by not knowing if infant nervous system damage was due to the effects of a specific drug, such as cocaine, or the effects of other associated factors, such as maternal depression, poor prenatal care, and other drug use, that are often linked with maternal drug use during pregnancy," Dr. Philip Sanford Zeskind, lead researcher at Levine Children's Hospital at Carolinas Medical Center in North Carolina, said in a statement.

Zeskind and his colleagues gathered data as part of a research initiative aimed toward understanding the effect drug abuse has on the mother child relationship, dubbed the Cocaine Affect Mother-Infant Dyads (CAMID). Evidence from previous research has shown that “hyperphonation,” a high-pitched spectral characteristic of an infant’s cry sound, could indicate nervous system damage caused by prenatal cocaine exposure.

The research team identified a spectral characteristic in the ultrasonic vocalizations of rat pups that were treated with prenatal cocaine exposure. This characteristic was similar to the pitch and acoustic structure of hyperphonation exhibited by infants who were exposed to cocaine during pregnancy. Even if a pediatric examination does not show any abnormalities, hyperphonation can still be a sign of health complications.

"The discovery of the similar spectral characteristic in rat pup vocalizations will allow for translational analyses 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," Zeskind added.

According to the American Pregnancy Association, cocaine elimination in a fetus is a much slower process compared to adults, meaning cocaine stays in an infant’s system longer than it does in the mother. Infants exposed to cocaine during pregnancy have a higher risk of suffering from genital, kidneys, brain, and overall growth defects. Exposing an infant to cocaine in the later stages of pregnancy increases their risk of dependence and withdrawal symptoms, including tremors, sleeplessness, muscle spasms, and trouble eating.

Source: Zeskin P. PLOS ONE. 2014.