In the journal PLOS ONE, researchers looked at foetal responses to voice and touch by asking pregnant women between their 21st and 33rd week of pregnancy to try out three different behaviours.
When the mothers rubbed their bellies, the babies had more arm, head, and mouth movements than when the women did nothing or when they spoke to the baby.
The authors wrote: "Although it is speculative to suggest, it might well be that the increases in arm movements in response to maternal touch are also directed responses towards the source of the stimulation."
Researchers invited 23 pregnant women into a dark room and asked them to try three different behaviours in different periods of time.
In the first situation, mothers were asked to read to their baby (Three Little Pigs or Jack and the Beanstalk).
In the second situation, the mothers were asked to stroke and rub their abdomen, and in the third they laid down with their arms at their side.
During each scenario, researchers used sonography to see how the baby responded.
In all scenarios, it was the mother's touch and rubbing their belly that elicited the most noticeable response.
The researchers said they were aware this was a small sample size, but it does complement findings that communication with your unborn baby is beneficial.
It's previously been found that unborn babies can "grimace" in the womb, after 4D scanners showed that by 36 weeks the children were able to create "complex multi-dimensional expressions" such as pain.
Researchers said they are "practising" facial expressions of pain while they are in the womb so that they can communicate any distress or pain they might feel.