A baby born prematurely often has to be separated from its parents and placed in an incubator in intensive care. For several weeks, he or she will undergo routine medical procedures that can be painful if not relieved by too many pharmaceutical pain relievers, which are risky for their development.
So how can we act for the baby's sake? A team from the University of Geneva (UNIGE), in collaboration with the Hospital Parini and the University of Valle d'Aosta, in Italy, observed that when a mother talks to her baby at the time of medical intervention, the signs of the expression of pain the baby's levels decrease and their level of oxytocin – the hormone involved in affective bonding and also linked to stress – has increased significantly, which could allow for better pain management.
These results, published in magazine Scientific Reports, demonstrate the importance of parental presence with premature babies, who are subjected to intense stress from birth, a presence that has a real impact on their well-being and development.
As soon as they are born before 37 weeks of gestation, premature babies are separated from their parents and placed in an incubator, often in intensive care.
They must undergo daily medical interventions necessary to keep them alive (intubation, blood collection, feeding tube, etc.), which have potential impacts on their development and pain management.
The difficulty? It is not always possible to relieve them with pharmaceutical analgesics, as the short- and long-term side effects on their neurological development can be significant. There are other ways to soothe the baby, such as wrapping, holding, sugary solutions or non-nutritive sucking with a teat.
However, for several years, studies have shown that the presence of the mother or father has a real calming effect on the child, particularly through the emotional modulations of the voice.
That is why Didier Grandjean's team, head professor in the Psychology Section of the Faculty of Psychology and Educational Sciences (FPSE) and the Swiss Center for Affective Sciences (CISA) at UNIGE, has been interested in early vocal contact between the mother and the premature baby, on the impact of the mother's voice on pain management resulting from the routine practices necessary for monitoring the babies, and on the psychological and cerebral mechanisms that may be involved.
To test this hypothesis, scientists followed 20 premature babies at the Parini Hospital in Italy and asked the mother to be present during the daily blood test, which is done by extracting a few drops of blood from the baby's heel. “We concentrated this study on the maternal voice, because in the first days of life it is more difficult for the father to be present, due to working conditions that do not always allow days off”, says Dr. Manuela Filippa, researcher in Didier Grandjean's group and first author of the study.
The study was carried out in three phases over three days, allowing for comparison: a first injection was taken without the mother present, a second with the mother talking to the baby and a third with the mother singing to the baby. The order of these conditions changed randomly. “For the study, the mother started talking or singing five minutes before the injection, during the injection and after the procedure,” says the Geneva investigator. We also measure voice intensity to cover the surrounding noise, as intensive care is often noisy due to ventilations and other medical devices.
First, the research team looked at whether the baby's pain diminished in the mother's presence. To this end, they used the Preterm Infant Pain Profile (PIPP), which establishes a coding grid between 0 and 21 for facial expressions and physiological parameters (heartbeat, oxygenation) that attest to the baby's painful feelings. “In order to encode the behavior of the preterm babies, we filmed each blood test and judged the videos 'blind' by trained personnel, without sound, so as not to know whether the mother was present or not,” notes Didier Grandjean.
The results are significant: the PIPP is 4,5 when the mother is absent and drops to 3 when the mother talks to her baby. “When the mother sings, the PIPP is 3,8. This difference with the spoken voice can be explained by the fact that the mother adapts her vocal intonations less to what she perceives in her baby when singing, because she is somewhat limited by the melodic structure, which is not the case when speaking" , emphasizes the professor from Geneva.
Scientists then looked at what changes in the baby when he hears his mother speak. “We quickly resorted to oxytocin, the so-called hormone of affection and empathy, which previous studies have linked to stress, family separation and pain”, explains Dr. Manuela Filippa. Using a saliva sample before the mother speaks or sings and after the heel prick, the research team found that oxytocin levels rose from 0,8 picograms per milliliter to 1,4 when the mother spoke. “In terms of oxytocin, this is a significant increase”, says the researcher.
These results show the positive impact of the mother's presence when premature babies undergo painful medical procedures. “We demonstrate here the importance of bringing parents and children together, especially in the delicate context of intensive care”, emphasizes Manuela Filippa.
“Furthermore, parents play a protective role here and can act and feel involved in helping their child to be his or her best child, which reinforces the essential bonds that are taken for granted in a full-time birth.” concludes Didier Grandjean.
Author António Piedade is a Biochemist and Science Communicator. He published over 700 articles and chronicles of scientific dissemination in the Portuguese press and 20 articles in international scientific journals.
He is the author of nine books on science dissemination, among which “Iris Científica” (Mar da Palavra, 2005 – National Reading Plan) stand out, “Caminhos de Ciência” with a preface by Carlos Fiolhais (Imprensa Universidade de Coimbra, 2011) and “Diálogos com Ciência” (Ed. Trinta por um Linha, 2019 – National Reading Plan) prefaced by Carlos Fiolhais.
It regularly organizes cycles of scientific dissemination lectures, including the already very popular “Ciência à Seis”, at the Rómulo Centro Ciência Viva of the University of Coimbra.
He regularly gives lectures on scientific dissemination in schools and other institutions.
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