If the taste of kale makes you make a face, you're not the only one: researchers have observed foetuses cry when exposed to the greens in the womb.

The team says the new research is the first to look at the response of unborn babies to different flavours.

In the past, researchers looked at what happens after birth in terms of what the offspring likes, but now they are looking at the facial expressions of the unborn child when they are hit by bitter or non-bitter tastes.

Grimacing foetus.

Foetuses showed a crying expression around twice as often when the mother consumed a kale capsule compared with carrot. Photograph: FETAP (Fetal Taste Preferences) Study/Fetal and Neonatal Research Lab/Durham University/PA

There were aromas from the mother's diet in theamniotic fluid. The taste buds can detect taste-related chemicals from 14 weeks of age.

The team looked at the scans of almost 70 pregnant women from the north-eastern part of England to see if the foetuses differed in flavour. One group was asked to take a capsule of powdered kale while the other was told to take a capsule of carrot. There was no difference in vegetable consumption by the mothers between the two groups.

The team looked at scans from women who were not given any capsule.

The women were told not to eat anything else before their scans.

A frame-by-frame analysis of the facial movements of the foetuses included combinations that looked like laughing or crying.

The researchers scanned 99 foetuses at either 32 weeks or 36 weeks.

When the team looked at the results, they found that the crying expression of the unborn child was twice as much when the mother ate a kale capsule. When the mother ate a carrot capsule, the foetuses adopted a laughter-like expression about twice as often as they did when she didn't eat any.

The clarity of the results was surprising according to the author of the work.

He said that they meant that the mother had not finished her meal when the foetus was already aware.

Beyza Ustun said the team was looking to explore the reaction of babies after birth to different flavours. She hoped that they would see less negative reactions if they were exposed to it before birth.

The study could be used to talk to pregnant women about their eating habits. Babies are less picky if the mother has a varied diet of vegetables and fruits.

Dr Julie Mennella, an expert in the field from the Monell Chemical Senses Center in the US, was not involved in the study.

She warned that the pregnant women were not randomised to experimental or control groups, and that the foetuses in the control group were not known.

The work provided a glimpse into the world of the human fetus.

Future work that highlights individual differences in foetal responses to flavours will be of interest.