[ARTICLE] Skin-to-skin contact: an effective anti-stress strategy that also favourably impacts the gut microbiota

Birth is an intensely stressful event for both the baby and the mother. Stress hormones help the baby adapt to the new, cold, dry, and oxygen-rich environment outside the womb. However, excessive stress can be harmful. Fortunately, the body has anti-stress mechanisms in place. While stress is mediated by the activation of the hypothalamic-pituitary-adrenal axis and the secretion of adrenaline and cortisol, anti-stress responses depend on the release of oxytocin from the central nervous system (1).

Immediate physiological regulation and emotional bonding after the stressful birth

Skin-to-skin contact (SSC) immediately after birth has been widely recognised for its profound anti-stress benefits for both newborns and their parents. Also known as “kangaroo care”, this practice involves placing the naked baby on one of its parents’ bare chest. In the short term, SSC helps stabilise the heart rate, respiratory rate, and temperature of newborns, which are essential indicators of reduced stress, together with lower levels of cortisol. SSC has also been shown to reduce the perception of pain in newborns, during routine procedures like blood draws or vaccinations. The release of oxytocin, facilitated by the tactile interaction, plays a significant role in mitigating pain and stress responses. On the parents’ end, SSC fosters a deep emotional bond with their newborn. This connection promotes a sense of confidence and competence in caring for their baby. The release of oxytocin during SSC not only calms the baby but also reduces stress and anxiety in parents, creating a mutual benefit (1,2).

More breastfeeding, less post-partum depression

Beyond immediate benefits, SSC can significantly lower the risk of postpartum depression, and reduce infantile mortality rate, especially in preterm babies. Lastly, SSC stimulates lactation and favours the initiation and maintenance of breastfeeding (2–4). The World Health Organization includes SSC during the first hour after birth as one of the ten steps to successful breastfeeding, which is highly recommended for health benefits during the first six months of life. In the longer term, SSC is likely to yield better health outcomes, including improved cerebral and cardiovascular system development (5). Therefore, SSC sessions are encouraged during the first hour after birth and as frequently as possible during the first weeks of life, in premature and fragile newborns as well as in healthy full-term babies.

Skin-to-skin contact could direct the gut microbiota to provide additional health benefits

Beyond the role of anti-stress hormones, the benefits of SSC may be amplified by the gut microbiota. A recent randomised controlled trial compared daily 1-hour sessions of SSC over five weeks with care-as-usual in healthy full-term infants. The researchers found differences in gut microbiota composition between the groups at two and five weeks of life. They did not attribute these differences to the direct transmission of microbes from the mother’s skin to the infant’s mouth, nor to the impact of breastfeeding, as rates of breastfed infants were similar in both groups. Instead, the authors proposed that the de-stressing effect of SSC influenced the colonisation of the infant gut by microbes and the subsequent maturation of the microbiota. Moreover, they discovered that the abundance of bacteria with favourable metabolic pathways, such as the ability to produce short-chain fatty acids, was higher in the SSC group. These bacterial characteristics are known to promote health benefits. Thus, SSC could initiate a virtuous cycle of health benefits through its de-stressing properties, involving the gut microbiota (6).

Humans have every interest in taking inspiration from kangaroos to take care of their offspring, up to a certain point…

References:

1. Uvnäs-Moberg K, Gross MM, Calleja-Agius J, Turner JD. The Yin and Yang of the oxytocin and stress systems: opposites, yet interdependent and intertwined determinants of lifelong health trajectories. Front Endocrinol (Lausanne). 2024 Apr 16;15:1272270.

2. Moore ER, Bergman N, Anderson GC, Medley N. Early skin-to-skin contact for mothers and their healthy newborn infants. Cochrane Database Syst Rev. 2016 Nov 25;11(11):CD003519.

3. Bedetti L, Lugli L, Bertoncelli N, Spaggiari E, Garetti E, Lucaccioni L, et al. Early Skin-to-Skin Contact in Preterm Infants: Is It Safe? An Italian Experience. Children (Basel). 2023 Mar 17;10(3):570.

4. Ali NB, Priyanka SS, Bhui BR, Herrera S, Azad MdR, Karim A, et al. Prevalence and factors associated with skin-to-skin contact (SSC) practice: findings from a population-based cross-sectional survey in 10 selected districts of Bangladesh. BMC Pregnancy and Childbirth. 2021 Oct 22;21(1):709.

5. WHO/UNICEF. Implementation guidance: protecting, promoting and supporting breastfeeding in facilities providing maternity and newborn services – the revised Baby‐friendly Hospital Initiative [Internet]. Geneva: World Health Organization; 2018. Report No.: CC BY‐NC‐SA 3.0 IGO. Available from: https://www.who.int/publications/i/item/9789241513807

6. Eckermann HA, Meijer J, Cooijmans K, Lahti L, de Weerth C. Daily skin-to-skin contact alters microbiota development in healthy full-term infants. Gut Microbes. 2024 Dec 31;16(1):2295403.