08 August 2019
By Alithea Williams
Here at SPUC, we come across all sorts of amazing stories about the development of unborn babies in the womb. Some of the scientific studies we read are trying to answer important questions such as when a baby feels pain, but some are looking that questions we never knew needed answering - such as what music babies like and if they understand different languages! So here's five questions and answers that give another angle on life before birth.
Can unborn babies tell the difference between someone speaking to them in English or Japanese?
Researchers at the University of Kansas knew that research had already shown that newborn babies may be sensitive to the rhythmic differences between languages, but they wanted to find out if this sensitivity actually started before birth. So, a bilingual speaker made two recordings of a passage, one in English, and one in Japanese, which were played to the unborn babies of 24 woman. The researchers used non-invasive sensing technology to measure changes in fetal heart rate. They found that when the babies heard the unfamiliar, rhythmically distinct language (Japanese) after having heard a passage of English, the foetal heart rates changed!
The news was an "extremely exciting finding for basic science research on language," Utako Minai, associate professor of linguistics and the team leader on the study, said. "These results suggest that language development may indeed start in utero. Fetuses are tuning their ears to the language they are going to acquire even before they are born, based on the speech signals available to them in utero. Pre-natal sensitivity to the rhythmic properties of language may provide children with one of the very first building blocks in acquiring language."
Why do babies kick in the womb?
Feeling your baby kick in the womb for the first time is an exciting moment. Mothers start feeling movements between 16-25 weeks gestation (though spontaneous movement starts at 7 weeks!) But while babies moving around is accepted as a normal part of pregnancy, it hasn't been clear exactly why it happens.
However, scientists now think they've found the answer. According to a study published in the journal Development, scientists at Trinity College Dublin found that babies move around because they are trying to develop strong bones and joints.
Can an unborn baby really send stem cells to repair its mother's organs?
This one is truly amazing. A few years ago, a meme was circulating claiming that during pregnancy, if the mother suffers organ damage, the baby in the womb sends stem cells to repair the damaged organ. Memes (even pro-life ones) aren't always accurate, but Snopes.com investigated this one and concluded that "the science behind the claim is actually fairly solid".
The transfer and incorporation of foetal stem cells into a mother's organs is referred to as fetomaternal microchimerism, and scientists have been generally aware of it for decades. Then, a 2015 study published in the journal Circulation Research addressed the issue of foetal stem cells actually healing maternal organs. In this study, researchers tagged mice with a fluorescent protein that allowed the researchers to trace the flow of the foetus's stem cells from the mother's placenta into its heart while they induced cardiac injury to the mother. They found that foetal stem cells directly targeted the damaged cardiac cells and fully integrated themselves into the mother's heart.
The authors said they had potentially uncovered "an evolutionary mechanism whereby the fetus assists in protecting the mother's heart during and after pregnancy." There is a wide body of research that suggests similar phenomena could occur in humans.
Do babies feel pain in the first trimester?
A rather more serious question.
A study published in the Journal Cell on 23 March 2017 reveals that the nervous system of embryos and foetuses may be greatly more developed than was previously believed. Entitled "Tridimensional Visualization and Analysis of Early Human Development" the study shows that unborn babies in the first trimester have "adult-like" patterns of nerves. Researchers "combined whole-mount immunostaining, 3DISCO clearing, and light-sheet imaging to start building a 3D cellular map" and found that "the adult-like pattern of skin innervation is established before the end of the first trimester, showing important intra- and inter-individual variations in nerve branches."
Whilst scientists will be cautious about concluding that the system of nerves observed in embryos and fetuses would allow the infant in development to feel pain, it would be sensible to consider that this is very possible. The new research does show that the nervous system develops much sooner than had previously been thought, which could point to pain sensitivity.
Do unborn babies prefer Mozart or the YMCA?
And, finally the one you've been waiting for.
In 2015, the Institut Marquès in Barcelona did pioneering research into the ability of unborn babies to listen and respond to music - they found that when it was transmitted intravaginally, babies responded to music from 16 weeks gestation!
Of course, the next thing the researchers wanted to know was what music unborn babies prefer to hear.
In June, the Institut published a new study, where they studied mouth and tongue movements of 300 fetuses between 18 and 38 weeks of gestation exposed to 15 different songs of three different music genres: classical, traditional, and pop-rock.
For context, the mouth and tongue movements studied are only spontaneously produced from 3-5% of babies in the second and third trimesters. The music genre causing the highest percentage of babies moving their mouth was classical music (84%), followed by traditional music (79%), and finally pop rock music (59%). Once the babies are able to stick out their tongues (protrusion), classical music is again their favourite music genre with 35%, followed by traditional music (20%) and pop-rock (15%).
However, there were some interesting variations. While pop-rock generally stimulated babies the least, 'Bohemian Rhapsody' by Queen and the 'YMCA' by the Village People both got a mouth movement score of 90%! Adele's 'Someone like you' and Shakira's 'Waka Waka' were both much less popular, with 60% and 50%.
So, from 16 weeks gestation, babies can hear music, respond to and learn from it, and even prefer Mozart to Adele. The unborn are amazing!