(Photo by Natalia Bostan on Shutterstock)

MEXICO CITY — Studies have shown that listening to classical music yields some remarkable positive effects on the brain and heart. It turns out, that your favorite Mozart or Beethoven piece might also be good for unborn babies too. Recent research from Mexican scientists demonstrates how classical music changes the way their hearts beat, and these changes might benefit their early development.

Heart rate variability, the tiny differences in timing between heartbeats, tells us about a baby’s developing nervous system. More variable heart patterns often signal healthy development, while less variation might indicate stress or other issues. This makes heart rate patterns an important window into fetal well-being.

Researchers at several Mexican universities and medical centers studied 37 pregnant women in their third trimester of pregnancy. They wanted to understand exactly how classical music might influence these delicate heart patterns in developing babies.

Starting with 100 pregnant volunteers, the research team ultimately focused on 37 participants whose fetal heart recordings were clear enough for detailed analysis. Getting precise measurements of fetal heartbeats isn’t easy. The signals must be very clear and consistent to measure the tiny variations between beats. Many recordings had too much interference or gaps to be reliable.

The study design was straightforward but carefully controlled. The researchers selected two five-minute classical pieces: “The Swan” by French composer Camille Saint-Saëns and “Arpa de Oro” by Mexican composer Abundio Martínez. Both pieces feature gentle, melodic qualities suitable for fetal hearing. The music played through specialized headphones placed on the mothers’ bellies, with volume kept at a safe level similar to normal conversation.

LISTEN: “The Swan”

“Overall, we discovered that exposure to music resulted in more stable and predictable fetal heart rate patterns,” said study author Claudia Lerma, from the National Institute of Cardiology Ignacio Chávez, in a statement. After hearing the music, the babies’ heartbeats showed more regular timing between beats, suggesting their nervous systems were responding to the musical stimulation in a controlled way.

Interestingly, the Mexican piece “Arpa de Oro” appeared to have a stronger effect than “The Swan.”

“The second piece appeared to have a stronger impact on some measures, indicating that it produced heart rate patterns that were more predictable and regular,” explained co-author Eric Alonso Abarca-Castro, from the Metropolitan Autonomous University Campus Lerma. “Factors like rhythmic characteristics, melodic structure, or cultural familiarity may be linked to this differentiation.”

LISTEN: “Arpa de Oro”

The study, published in Chaos, went beyond traditional methods of measuring fetal heart rate. Instead of just counting beats per minute, researchers used advanced mathematical analysis to examine the precise timing and patterns between individual heartbeats. This detailed approach revealed how the babies’ nervous systems were responding to the music in real time.

One particularly interesting finding emerged after the music stopped playing. The babies maintained more stable heart patterns than before hearing the music, and researchers noted more frequent heart rate accelerations – rapid increases in heart rate that often indicate fetal movement or response to stimulation.

“Our results suggest that these changes in fetal heart rate dynamics occur instantly in short-term fluctuations,” said Abarca-Castro. “Parents who play soothing music may stimulate and benefit the fetal autonomic system.”

The findings suggest that gentle classical music might help support healthy fetal development by promoting stable heart rate patterns. Like a well-conducted orchestra, the interaction between musical stimuli and fetal response appears to follow patterns that we are only beginning to understand.