Impact of breastfeeding on the cranial development of the newborn

The newborn does not suck only to feed, but builds with the mouth the balance of his body and his development. –  Dr. Michel Odent

Breastfeeding is not just a nutritional behavior, but a complex functional act that significantly affects the morphological and functional development of the skull and orofacial structures of the newborn. Growing scientific evidence shows that physiological breastfeeding promotes a harmonious, symmetrical, and proportionate cranial development, by virtue of the mechanical forces exerted during the feeding act and the specific neuromuscular activation of the orofacial components.

This article explores the mechanisms through which breastfeeding modulates the shape of the skull, contributes to facial symmetry, stimulates transverse growth of the palate, and promotes adequate mandibular and postural development. Clinical implications in the prevention of positional plagiocephaly, malocclusions, and oral respiratory dysfunctions are also discussed.

Morphogenetic dynamism and fetal cranial plasticity

Fetal cranial development originates as early as the first weeks of gestation and follows a well-orchestrated sequence of morphogenetic events involving the embryonic layers, particularly the ectoderm and the paraxial mesoderm. The cranial primordium takes shape from the fourth week of intrauterine life, with the formation of the occipital somites and the migration of neural crest cells, fundamental for the constitution of the craniofacial skeleton, the meninges, and the peripheral nervous system.

The cranial base (neurocranium) develops by endochondral chondrification, while the cranial vault (calvaria) and the viscerocranium form predominantly through direct membranous ossification. The cranial sutures (sagittal, coronal, lambdoid, metopic) remain open to allow for the rapid growth of the brain volume, which increases from about 75 ml at the 20th week of gestation to over 370 ml at the end of pregnancy.

From the second trimester onwards, the fetal skull assumes a typical configuration: the cranial vault is composed of thin and relatively flexible bones, separated by sutures and fontanelles, while the cranial base consolidates progressively to provide support for brain formation and sensory pathways. Cranial plasticity is functional not only to brain growth but also to the future ability of the skull to adapt to compressive forces during vaginal delivery.

Newborn cranial molding

The passage of the newborn through the birth canal represents a critical biomechanical event that imposes compressive, shearing, and torsional forces on the skull. To cope with this biomechanical challenge, the newborn has a highly adaptable cranial structure:

• The cranial sutures act as mobile fibrous joints, allowing a phenomenon of overlapping among the parietal, frontal, and occipital bones.
• The fontanelles (anterior and posterior), regions of non-ossified connective membrane, function as pressure-absorbing zones and expansion spaces.
• The bones of the cranial vault (particularly the parietals and occipital) are deformable and not completely fused, which allows temporary reshaping of the cranial form to facilitate expulsion.

During vaginal delivery, the fetal head undergoes dynamic molding, which may result in transient morphological variations (such as asymmetries, flattenings, protrusions) that physiologically resolve in the first postnatal weeks, provided that neuromuscular and postural adaptation is effective.

The mode of delivery greatly influences these adaptations:

• Prolonged or difficult vaginal births may increase the degree of compression and the risk of persistent asymmetries (molding plagiocephaly, cranial torsions).
• Cesarean sections, on the other hand, reduce the exposure of the skull to compressive forces but may compromise the activation of some neuro-postural reflexes linked to the birth canal.

Anatomical and functional characteristics of the neonatal skull post-partum

In the period immediately following birth, the newborn’s skull presents as an incomplete, flexible, and dynamic structure, designed to accompany the explosive growth of the brain in the first years of life. The main anatomical and functional characteristics are:

• High plasticity: the sutures and fontanelles allow morphological variations functional to postural load and environmental interaction.
• Physiological asymmetries: frequently present in the first days, they are compatible with molding during birth and resolve spontaneously under conditions of adequate stimulation.
• Cranial volume: at birth, the brain represents about 25% of the adult brain volume, but reaches 75% by the second year of life. The skull grows in response to the pressure exerted by brain growth (Virchow’s theory).
• Relationship with the orofacial system: cranial structures are in close functional relationship with the mandible, palate, oral and cervical muscles, involved in sucking and postural control.
• Unstable cranial base: the articulations between basal bones (such as the spheno-occipital synchondrosis) are not yet fused, influencing head posture and neuromotor balance.
• Head-body ratio: the head’s weight is disproportionately large compared to the body, with a very anterior center of gravity, conditioning sucking, breathing, and swallowing patterns.

Biomechanical influence of breastfeeding suction on cranial and facial development

Contemporary scientific literature has now clarified that the mode of feeding in the first months of life not only influences nutrition and immunity, but also profoundly affects the shape and harmony of the newborn’s skull.
The act of sucking at the breast activates physiological muscular patterns that directly influence the morphological organization of the facial mass and cranial base. The newborn is born with a highly plastic skull, characterized by thin bones, mobile sutures, and open fontanelles, elements that allow rapid brain growth and adaptation to environmental mechanical stresses. Among these stimuli, breastfeeding plays a fundamental role in promoting proper craniofacial development.

During breastfeeding, the newborn exerts an intraoral negative suction thanks to an active and synergistic coordination of mandibular, lingual, labial, and buccinator muscles. The mandible performs antero-inferior movements, with rhythmic activation of the pterygoid, masseter, and digastric muscles. This cyclic movement produces traction and compression on the developing bone tissues, triggering remodeling and bone growth processes, according to the principles of skeletal biomechanics.

The oral cavity and the newborn’s palate, in particular, receive transverse and anteroposterior stimulation that favors their harmonious expansion. In contrast, bottle feeding generates passive suction, with less muscular activation and limited biomechanical impact, predisposing to high-arched palate and malocclusions.

The act of sucking at the breast promotes functional symmetry of the mandibular hemiarches and parietal bones thanks to an equal distribution of bilateral muscular load. This contributes to the harmonious and proportionate development of the skull, preventing structural asymmetries. Moreover, the natural position during breastfeeding, which favors skin-to-skin contact and physiological head flexion, prevents posterior cranial flattening, reducing the risk of positional plagiocephaly.

Morphogenetic and functional role of breastfeeding

Symmetrical oromandibular activity is also correlated with balanced development of the mandibular condyles and temporomandibular joints (TMJ), contributing to good occlusal and postural function over time.

Craniofacial development influenced by breastfeeding also has implications for the upper respiratory system. A well-developed palate and a correctly positioned mandible allow optimal patency of the upper airways, reducing the risk of chronic oral breathing and obstructive sleep apnea in infants.

The evidence of a correlation between breastfeeding and harmonious cranial development has important implications in the pediatric, orthodontic, osteopathic, and speech therapy fields. Early support for natural breastfeeding can represent an effective preventive intervention against:

• Positional plagiocephaly
• High-arched palate
• Retrognathia
• Dental malocclusions
• Oral dysfunctions (atypical swallowing, oral breathing)

The integrated analysis of neonatal cranial development highlights how breastfeeding represents not only an optimal nutritional strategy, but also a fundamental morphogenetic determinant in the construction of craniofacial harmony and functionality. The biomechanical and neuromuscular forces generated by physiological breastfeeding actively stimulate the modeling of cranial structures, promoting symmetrical and proportionate growth of the neurocranium and viscerocranium.

Such functional stimuli, in close interaction with postnatal anatomical characteristics (open sutures, fontanelles, thin bones), contribute to the prevention of postural plagiocephalies, occlusal dysmorphisms, and orofacial dysfunctions. Moreover, correct cranial development facilitates the maturation of respiratory, oral, and postural functions, supporting a neuromotor and sensory organization consistent with the principles of developmental neurophysiology.