Babies react to flavors in the womb and prefer carrots over kale

4D ultrasound images show fetuses respond to taste and smell.
Brittney Grimes
Baby in the womb has facial expressions.
Baby in the womb has facial expressions.

APS/Psychological Science 

Fetuses prefer certain flavors and show their expressions when exposed to different tastes and smells. Researchers have found evidence that babies in the womb respond to flavors transferred when their mothers ate carrots and kale.

According to the study, the research team from the Fetal and Neonatal Research Lab at Durham University scanned pregnant women and their fetuses. They were able to determine that fetuses can distinguish different flavors very early.

4D ultrasound to detect fetal reaction

The researchers, which also included scientists from Aston University, Birmingham, UK, and the National Center for Scientific Research-University of Burgundy, France, used nonmedical 4D ulstrasound scans for the study.

The pregnant women were asked not to eat food in the hour prior to their appointment. Then, each mother was given a capsule containing either the flavor of carrots or kale. One capsule contained approximately 400 milligrams of carrot powder or 400 milligrams of kale powder. There was also a control group, which consisted of mothers who did not ingest either capsule. In total, 100 mothers between the ages of 18 and 40 years old participated in the study.

Time period of study

Researchers conducted 12- and 20-week scans on each mother. They could see the fetuses on the screens and their reactions to the vegetables. Specifically for this study, all women underwent the 4D ultrasound at 32- and 36-week gestation. However, there were a few variables in the testing, due to COVID-19 restrictions or some women had given birth before their 36-week scans.

Facial expressions after exposure to the vegetables

The fetuses responded to their mothers’ ingestion of the vegetables. Most of the fetuses exposed to kale seemed to have “cry-face” responses, while those exposed to carrots showed “laugh-face” reactions.

The researchers said in a statement, “This study sheds new light not only on fetal sensory abilities but also on the specificity of facial responses to different flavors relating to their discriminative abilities.”

Sensory within the womb

It was often believed that fetuses determined taste and smell from food eaten by their mothers by swallowing and inhaling the amniotic fluid. New evidence from this study shows that fetuses do discriminate different flavors in the amniotic fluid prenatally, and not just from postnatal sensory exposure.

"A number of studies have suggested that babies can taste and smell in the womb, but they are based on post-birth outcomes, while our study is the first to see these reactions prior to birth” said lead researcher Beyza Ustun, a postgraduate researcher in the Fetal and Neonatal Research Lab, Department of Psychology at Durham University.

The research was published in the journal Psychological Science.

Future meaning of this study

Findings unearthed by this study could advance our understanding in the development of human taste and smell receptors. Researchers also believe this study could help establish healthy eating habits for babies and figure out their food preferences after birth.