ABSTRACT
Background
Further studies are needed to better characterize the association between craniofacial growth and feeding methods in infants aged 0–6 months.
Objective
To evaluate the longitudinal association between feeding modality (exclusive breastfeeding versus mixed feeding) and craniofacial growth in infants aged 0–6 months.
Study Design
Observational, analytical, longitudinal cohort study.
Subjects
A total of 120 infants were evaluated four times.
Outcome Measures
Nine craniofacial variables were assessed: four width, two height, and three depth measurements.
Statistical Analysis
Growth increments were estimated by feeding type, and linear mixed models were used to assess associations with craniofacial development.
Results
Exclusively breastfed infants showed greater increases in anthropometric and craniofacial measures compared with mixed feeding. Significant differences were observed in total craniofacial height (3.50 ± 0.08 vs. 3.25 ± 0.01 cm; p = 0.046), anterior facial height (2.08 ± 0.40 vs. 1.76 ± 0.07 cm; p = 0.016), maxillary depth (2.33 ± 0.04 vs. 2.21 ± 0.11 cm; p = 0.007), and mandibular depth (2.55 ± 0.02 vs. 2.41 ± 0.12 cm; p = 0.040).
Conclusion
Exclusive breastfeeding was associated with greater craniofacial growth from 0 to 6 months compared with mixed feeding, supporting its role in early craniofacial development.
Keywords: anthropometry, breast feeding, craniofacial development, growth, infant, newborn, sucking behavior
Why This Paper Is Important to Pediatric Dentists.
Early feeding type (exclusive breastfeeding vs. artificial feeding) significantly influences craniofacial growth during the first months of life, shaping maxillary and mandibular development.
Breastfeeding provides functional orofacial stimulation that may help prevent malocclusions and parafunctional habits, supporting better long‐term oral health.
Understanding these growth patterns enables paediatric dentists to identify at‐risk infants early, guide parents on feeding practices, and implement timely preventive interventions.
1. Introduction
General growth (weight and length) and craniofacial development during the first year of life are determined by the interaction of genetic and environmental factors [1, 2]. Among the latter, notable influences include prenatal, perinatal, and postnatal health status [2, 3]; gestational age; birth weight; socioeconomic conditions; family and cultural environment; as well as breastfeeding, which provides not only nutritional benefits [4, 5, 6], but also functional advantages derived from the neuromotor activity performed by the infant during suckling [4, 7].
Maternal attitudes toward breastfeeding are a key determinant in the initiation, duration, and exclusivity of direct breastfeeding, which may indirectly influence both general and craniofacial growth. Studies by Hamze et al. [8] and Yuan et al. [9] highlight how maternal beliefs, perceptions, prior experiences, and the attitudes and knowledge of their partners shape decisions regarding exclusive breastfeeding and adherence. These psychosocial factors are relevant, as they can condition differences in orofacial stimulation and the functional maturation of the stomatognathic system during the first months of life.
Several investigations have described the effect of feeding type on the development of cranio‐maxillary structures, emphasizing that the physiological mechanism of nutritive sucking differs between infants fed directly at the breast and those fed formula milk via bottle [10, 11]. Direct breastfeeding promotes adequate craniofacial development through the activation of orofacial muscles, mandibular movements, and tongue positioning during suckling. This functional pattern stimulates maxillomandibular growth, favors nasal breathing, and contributes to the prevention of malocclusions and parafunctional habits and other functional alterations of the stomatognathic system that may compromise nutrition and long‐term health [5, 12]. In contrast, artificial feeding with formula milk via bottle requires less neuromotor stimulation and reduced orofacial muscle activation, potentially hindering skeletal development [12]. This condition increases the risk of dysfunctional oral habits, such as tongue thrusting and atypical swallowing, which may subsequently alter jaw size and position and predispose to malocclusions [5, 13].
The duration of breastfeeding has also been recognized as a relevant factor for craniofacial growth. A study conducted in Bogotá, Colombia, by González (2013) [14], among children aged 0–24 months reported that breastfeeding was the predominant feeding practice during the first six months of life. Beyond six months of age, 35% of children continued breastfeeding. In that study, breastfeeding duration was the factor most strongly associated with craniofacial growth, particularly head circumference, facial width, and maxillary and mandibular lengths. Similarly, Kumoi et al. [15], in a sample of 851 Asian children aged 2–5 years, observed more favorable maxillary and dental relationships among those breastfed for more than six months. Chen et al. [16], in Beijing, reported that breastfeeding for ≥ 6 months was associated with a lower prevalence of maxillary alterations and reduced prevalence of non‐nutritive sucking habits. Likewise, Boronat‐Catalá et al. [17] found a lower prevalence of malocclusions (11%) in children breastfed for more than 16 weeks compared with 23% in those breastfed for a shorter period.
Craniofacial growth (CFG) involves dynamic changes in the size and proportions of the skull and face, expressed in three dimensions: transverse (width), vertical (height), and sagittal (depth) [18]. Anthropometry remains a reliable, safe, and low‐risk method for assessing these changes in infants, with studies reporting intraclass correlation coefficients above 0.90 for cranial measurements [19, 20]. Furthermore, the availability of normative data through direct anthropometry and three‐dimensional scanning enables contextualized interpretations of craniofacial development [14].
Functional factors such as feeding type may thus influence craniofacial growth trajectories, as breastfeeding provides orofacial activation distinct from bottle feeding, potentially shaping the magnitude and direction of growth across all three dimensions. Globally, studies on early childhood growth have mainly focused on descriptive patterns and associated factors [21], forming a basis for public health strategies [21]. However, there remains a clear need for prospective studies that directly assess the effect of exclusive breastfeeding on craniofacial growth during the first six months of life compared with other feeding types [20, 22, 23, 24, 25]. Such knowledge would allow for the early detection of functional alterations and timely interventions to support optimal craniofacial and overall development.
1.1. Objective
To evaluate the longitudinal association between feeding modality (exclusive breastfeeding (EBF) versus mixed feeding (MF)) and craniofacial growth in infants aged 0–6 months.
2. Materials and Methods
2.1. Study Design
This observational, analytical, longitudinal cohort study was conducted in 2023. A total of 240 full‐term newborns (FNB) were initially recruited from the postpartum consultation at a health institution in Bogotá, Colombia. The study included 202 FNB infants aged 0–6 months who were systemically healthy, with gestational age between 37 and 41 weeks (GA), birth weight ≥ 2500 g, and fed either direct EBF up to six months, MF, or artificial feeding (AF). Exclusion criteria were FNB with craniofacial anomalies, syndromes, oral conditions hindering breastfeeding, neuromotor disorders, or cardiorespiratory alterations.
Each infant was evaluated at four time points over six months: Time 1 (T1) 0–33 days; Time 2 (T2) 60–119 days; Time 3 (T3) 120–179 days; and Time 4 (T4) 180–209 days. Independent variables included feeding type and sociodemographic factors (income, socioeconomic stratum, marital status, maternal education, and occupation). Functional oral variables, including number of suctions, pauses, and bursts, were measured from 2‐min video recordings for each observation, counting all suck cycles and recording pauses according to standardized definitions [23], while dependent variables were weight (g), length (cm), and nine craniofacial variables distributed as four width measurements: head width (cm), bizygomatic width (cm), head circumference (cm), and lower face width (cm); three depth measurements: sagittal dimension (LAPC) (cm), maxillary depth (MAX DEPTH) (cm), and mandibular depth (cm); and two height measurements: total craniofacial height (cm) and anterior facial height (cm) [23, 26].
Maternal and perinatal covariates were collected at baseline using a structured questionnaire and clinical records. These included marital status, maternal occupation, presence of maternal health conditions during pregnancy (yes/no), number of prenatal care visits, history of threatened abortion (yes/no), pregnancy‐related diseases (yes/no), substance use during pregnancy (yes/no), history of maternal trauma during pregnancy (yes/no), pregnancy planning (planned/unplanned), instrumental delivery (yes/no), socioeconomic status (classified into six levels according to the national classification), and mode of delivery (vaginal or cesarean section).
2.2. Sample
A non‐probabilistic, sequential, and consecutive sampling method was used for participants who met the inclusion and exclusion criteria. Recruitment began on January 10, 2023, with the first infant and ended on June 30, 2023, with the last participant. The final data were collected on January 15, 2024.
2.3. Sample Size Calculation
The sample size was calculated based on previous craniofacial growth studies [14, 23], considering a 5% minimum difference between mean craniofacial measurements of infants receiving EBF and AF at 6 months. With 90% power, the required size was statistically determined at 77 in each group.
During the early phase of data collection, an internal interim assessment was conducted after 32 infants completed two measurement occasions (T1 and T2). This assessment was performed exclusively to evaluate the observed variability of craniofacial growth parameters under real study conditions and was not a separate or previously published study. No hypothesis testing was conducted at this stage. Given the observed variability and the dynamic nature of feeding practices during follow‐up, the target sample size was recalculated to preserve the originally planned statistical power for all study outcomes. The minimum total sample size was determined based on the craniofacial variable exhibiting the largest variance, resulting in a required total of 100 infants. Ultimately, 202 infants were included; 120 completed all four assessments, while 82 contributed at least one observation. Feeding modality was time‐varying across follow‐up, and the distribution of infants by feeding category at each assessment period is shown in Figure 1.
FIGURE 1.
Feeding frequency and transition rates by type of feeding. Only EBF and MF were included due to the low number of AF cases.
2.4. Instrument Calibration
All measurement instruments were calibrated according to standards established by the World Health Organization (WHO) [21, 27]. Additionally, a single examiner was trained to ensure reliability in weight, length, and nine craniofacial measurements, following a standardized protocol described in a previously conducted pilot study, which provided methodological validity for the primary study [23].
2.5. Ethical Considerations
The research was conducted in compliance with the ethical principles outlined in the Declaration of Helsinki (JAMA, 2013) [28] and the International Guidelines for Biomedical Research Involving Human Subjects by CIOMS (2002), which emphasize scientific and social value, ethical review, informed consent, and protection of vulnerable groups. Additionally, the updated CIOMS/PAHO guidelines (2016) for research in resource‐limited settings were applied [29]. Ethical approval was obtained from the corresponding institutional review boards, and informed consent was obtained from all participants.
2.6. Statistical Analysis
Various statistical methods were employed to analyze the relationship between feeding type and craniofacial growth. First, descriptive statistics (mean and standard deviation) were applied to identify increases in craniofacial dimensions according to feeding type. Transition rates between feeding types (e.g., from EBF to MF) across the different follow‐up periods were also calculated.
To assess potential residual effects on craniofacial growth resulting from changes in feeding type, a carry‐over variable was defined [24, 25]. This variable was coded as follows: 1 if the infant transitioned from EBF to MF, −1 if the transition was from MF to EBF, and 0 if no changes occurred between the evaluated periods.
Since there were twelve maternal and perinatal control variables, these variables were transformed using Multiple Correspondence Analysis (MCA), resulting in four principal components that explained 60% of the variability of the twelve variables and facilitated the construction of a more parsimonious model.
Subsequently, growth models were fitted using the nlme package, model selection was performed via stepwise AIC with the cAIC4 package in R [26] statistical software (version 4.5.1–2025, open‐source). Additional standard R packages were utilized for data manipulation and visualization. Models were estimated using restricted maximum likelihood (REML), and analyses were stratified by age group and sex.
As an example, the analysis of MAX DEPTH is presented, although all response variables were modeled following the same structure. Each child was measured between one and four times during the follow‐up, so a linear mixed‐effects model with longitudinal ANOVA was used to account for the repeated‐measures structure over time.
Explanatory variables included principal components derived from maternal characteristics, baseline child measurements, and feeding type. Each predictor was initially evaluated individually, corresponding models were fitted, and the most relevant variables were selected based on the Akaike Information Criterion (AIC). Residual normality was assessed using the Kolmogorov–Smirnov test, and Box‐Cox transformations were applied when necessary to optimize model fit. These models accounted for the longitudinal structure of the data, intra‐individual variability, and other potential confounders.
3. Results
Table 1 summarizes the main sociodemographic characteristics of the sample, including maternal origin, marital status, social security coverage, socioeconomic status, household income, maternal education level, and occupation. Across follow‐up measurements, the distribution by sex remained consistent, with a higher proportion of males than females in all age groups.
TABLE 1.
Classification of sociodemographic variables.
| Variable | Category | n (%) |
|---|---|---|
| Mother's place of birth | National | 102 (50.50%) |
| Foreign | 100 (49.50%) | |
| Civil status | Married | 20 (9.90%) |
| Free union | 153 (75.70%) | |
| Single mother | 29 (14.40%) | |
| Social Security | Yes | 201 (99.50%) |
| No | 1 (0.50%) | |
| Socioeconomic stratum | Stratum 1 | 12 (5.90%) |
| Stratum 2 | 139 (68.80%) | |
| Stratum 3 | 51 (25.20%) | |
| Income | Less than one minimum wage | 27 (13.40%) |
| One minimum wage | 110 (54.70%) | |
| More than one minimum wage | 64 (31.80%) | |
| Mother's Education | University | 17 (8.40%) |
| Higher tecnical | 23 (11.40%) | |
| Complete secundary | 106 (52.50%) | |
| Incomplete secundary | 52 (25.70%) | |
| Complete primary | 4 (2.00%) | |
| Mother's occupation | Homemaker | 173 (85.60%) |
| Student | 4 (2.00%) | |
| Employee | 16 (7.90%) | |
| Self‐employed | 9 (4.50%) | |
| Sex | ||
| Time 1 | Male | 126 (62.37%) |
| Female | 76 (37.62%) | |
| Time 2 | Male | 81 (65.32%) |
| Female | 43 (34.67%) | |
| Time 3 | Male | 76 (63.33%) |
| Female | 44 (36.66%) | |
| Time 4 | Male | 78 (63.93%) |
| Female | 44 (36.06%) | |
The average frequency of EBF was between 8 AND 12 times per day. For MF, the average frequency of direct breastfeeding ranged from 5 to 10 times per day (68.1%), while the average intake of AF via bottle was 2 to 5 times per day (31.81%). For infants fed exclusively with AF (n = 6; 4.9%), the daily intake of formula ranged from 4.5 to 8.5 bottles per day (See Table 2).
TABLE 2.
Daily feeding frequency and distribution of infants by type of feeding across follow‐up periods T1–T4.
| Follow‐up Time/Age (days) | n (%) | Age/days Mean ± SD | EBF n (%) | MF n % | AF n (%) | Daily feeding frequency mean ± SD | |||
|---|---|---|---|---|---|---|---|---|---|
| EBF | MF | AF | |||||||
| EBF within MF | AF within MF | ||||||||
| T1 (0–33) | 202 (100) | 10.42 ± 6.45 | 180 (89.1) | 22 (10.89) | 0 (0) | 10.58 ± 1.89 | 8.72 ± 1.80 | 3.80 ± 2.30 | NA |
| T2 (60–119) | 124 (62.00) | 77.4 ± 11.0 | 89 (71.7) | 33 (26.60) | 2 (1.61) | 10.60 ± 2.76 | 8.57 ± 2.22 | 3.24 ± 1.76 | 6.5 ± 2.1 |
| T3 (120–179) | 120 (60.00) | 131.61 ± 9.78 | 74 (61.6) | 42 (35.00) | 4 (3.33) | 10.01 ± 2.51 | 7.97 ± 2.38 | 3.24 ± 1.51 | 6.5 ± 1.3 |
| T4 (180–209) | 122 (61.00) | 187.55 ± 6.98 | 66 (54.1) | 50 (40.98) | 6 (4.9) | 8.01 ± 3.08 | 6.48 ± 2.13 | 3.73 ± 1.74 | 6.5 ± 1.2 |
Note: Prepared by the authors based on the analysis of the study dataset.
Abbreviations: AFLA, artificial feeding; EBF, exclusive breastfeeding; MF, mixed feeding; SD, standard deviation.
3.1. Changes in General Anthropometric Parameters and Craniofacial Dimensions
The percentage of increase was calculated based on the difference between the mean values of each dimension by feeding type and follow‐up period: T1–T2 (0–59 days), T2–T3 (60–179 days), and T3–T4 (180–209 days), as shown in Table 3.
TABLE 3.
Average percentage growth in infants receiving EBF and MF across successive measurement periods.
| Growth Increment with EBF and MF (%) ± SEM | T1–T2 | T2–T3 | T3–T4 | |||
|---|---|---|---|---|---|---|
| EBF % (n = 87) | MF % (n = 8) | EBF % (n = 69) | MF % (n = 28) | EBF % (n = 63) | MF % (n = 45) | |
| Weight (g) | 70.5 ± 2.6 (p =0.0757) | 58.2 ± 7.4 | 24.0 ± 1.4 (p =0.3366) | 23.0 ± 1.9 | 11.0 ± 2.2 | 13.0 ± 1.3 (p =0.2178) |
| Length (cm) | 15.0 ± 0.6 (p =0.0774) | 12.5 ± 1.5 | 9.0 ± 0.6 (p =0.1023) | 7.5 ± 1.0 | 5.5 ± 0.5 | 7.0 ± 0.9 (p =0.0748) |
| Head circumference (cm) | 13.0 ± 0.4 (p =0.2251) | 12.0 ± 1.2 | 6.0 ± 0.3 (p =0.0020) | 4.5 ± 0.4 | 4.0 ± 0.3 (p =0.0843) | 3.5 ± 0.2 |
| Head width (cm) | 24.0 ± 0.9 (p =0.0001) | 12.0 ± 2.0 | 2.0 ± 0.8 | 7.0 ± 1.4 (p =0.0017) | 6.5 ± 0.8 | 7.5 ± 0.8 (p =1894) |
| Bizygomatic width (cm) | 14.0 ± 0.9 (p =0.1915) | 12.0 ± 2.0 | 7.0 ± 0.6 (p < 0.0010) | 2.0 ± 0.7 | 4.5 ± 0.5 | 8.7 ± 0.6 (p < 0.0001) |
| Lower facial width (cm) | 15.0 ± 1.0 (p =0.2252) | 12.5 ± 3.0 | 6.8 ± 0.6 p (0.0186) | 4.3 ± 1.0 | 4.2 ± 0.5 | 5.5 ± 0.6 (p =0.0497) |
| ACFT (cm) | 17.0 ± 0.8 (p =0.3308) | 15.5 ± 3.2 | 8.0 ± 0.8 (p =0.1373) | 6.5 ± 1.1 | 5.0 ± 0.8 | 5.5 ± 0.6 (0.3090) |
| AFANT (cm) | 18.0 ± 1.1 (p =0.2271) | 15.5 ± 3.0 | 8.8 ± 0.8 (p =0.0510) | 6.4 ± 1.2 | 6.5 ± 0.7 (p =0.3310) | 6.0 ± 0.9 |
| LAPC (cm) | 17.0 ± 1.0 (p =0.3797) | 16.0 ± 3.0 | 8.0 ± 0.8 | 8.4 ± 1.3 (p =0.3981) | 7.0 ± 0.7 (p =0.1746) | 6.0 ± 0.8 |
| MAX DEPTH (cm) | 16.6 ± 0.9 (p =0.3166) | 15. ± 3.1 | 8.0 ± 0.7 (p =0.0687) | 5.9 ± 1.2 | 5.7 ± 0.6 | 5.8 ± 0.7 (p =0.4569) |
| MAND DEPTH (cm) | 17.4 ± 0.9 (p =0.4918) | 17.3 ± 4.6 | 8.6 ± 0.8 (p =0.0757) | 6.5 ± 1.2 | 6.3 ± 0.6 (p =0.2945) | 5.8 ± 0.7 |
Note: T1–T2 = 0–59 days; T2–T3 = 60–179 days; T3–T4 = 180–209 days. Variables include general anthropometrics: Weight (g), Length (cm), Head circumference (cm), and craniofacial dimensions: Head width (cm), Bizygomatic width (cm), Lower facial width (cm), ACFT (fronto‐tragial arc, cm), AFANT (anterior facial height, cm), LAPC (cranial anterior–posterior length, cm), MAX DEPTH (maxillary depth, cm), and MAND DEPTH (mandibular depth, cm). The p‐values had been aggregated.
Between T1 and T2, infants fed with EBF showed higher percentage increases in all evaluated parameters compared to those receiving MF. This difference was particularly notable for weight (70.5% EBF vs. 58.2% MF), head width (24.0% EBF vs. 12.0% MF), and anterior facial height (18.0% EBF vs. 15.5% MF).
During the T2–T3 period, a general trend toward a slower growth rate was observed. Nevertheless, some differences in feeding type were evident. In infants with MF, head width showed a higher percentage increase (7.0%) compared to EBF infants (2.0%). In contrast, EBF infants showed greater increases in variables associated with maxillofacial dimensions, such as bizygomatic width (7.0%), lower facial width (6.8%), and mandibular depth (8.6%), with differences close to or exceeding 5% relative to MF infants.
In the T3–T4 period, growth was more homogeneous between groups; however, some craniofacial variables continued to show relevant differences. Bizygomatic width increased notably in MF infants (8.7%), exceeding the increase in EBF infants (4.5%) by more than 4 percentage points. Similarly, head width (7.5% vs. 6.5%) and lower facial width (5.5% vs. 4.2%) showed higher increases in the MF group. Conversely, EBF infants maintained slightly higher growth in variables such as maxillary depth (7.0%) and anterior facial height (6.5%).
From T1 to T4 (Table 4), infants receiving EBF showed higher absolute and percentage increases in both general anthropometric and craniofacial variables compared to those receiving MF.
TABLE 4.
Growth increments between T1 and T4 in infants receiving EBF and MF.
| Variable | Mean ± SD | Growth increments | ||||||
|---|---|---|---|---|---|---|---|---|
| EBF T1 | EBF T4 | MF T1 | MF T4 | EBF Mean | EBF % | MF Mean | MF % | |
| n | 180 | 66 | 22 | 50 | 66 | 66 | 22 | 22 |
| Weight (g) | 3246 ± 533 | 7654 ± 744 | 3382 ± 405 | 7488 ± 80 | 4408 ± 211 | 136 | 4106 ± 402 | 120 |
| Length (cm) | 51.37 ± 2.5 | 67.54 ± 2.21 | 52.1 ± 2.1 | 67.8 ± 2.9 | 16.17 ± 0.3 | 31.0 | 15.7 ± 0.85 | 30.10 |
| Head circumference (cm) | 35.2 ± 1.17 | 43.15 ± 1.14 | 35.7 ± 1.17 | 43.3 ± 1.2 | 7.94 ± 0.03 | 22.5 | 7.57 ± 0.3 | 21.20 |
| Head width (cm) | 9.4 ± 0.69 | 12.7 ± 0.83 | 9.68 ± 0.58 | 12.5 ± 0.9 | 3.3 ± 0.14 | 35.10 | 2.87 ± 0.37 | 29.60 |
| Bizygomatic width (cm) | 8.32 ± 0.50 | 10.53 ± 0.56 | 8.47 ± 0.50 | 10.5 ± 0.5 | 2.28 ± 0.60 | 27.40 | 2.06 ± 0.50 | 24.30 |
| Lower facial width (cm) | 7.85 ± 0.57 | 10.06 ± 0.53 | 8.01 ± 0.47 | 9.9 ± 0.54 | 2.21 ± 0.04 | 28.15 | 1.92 ± 0.07 | 23.90 |
| ACFT (cm) | 10.5 ± 0.63 | 13.99 ± 0.55 | 10.6 ± 0.69 | 13.8 ± 0.5 | 3.5 ± 0.08 | 33.40 | 3.25 ± 0.01 | 30.40 |
| AFANT (cm) | 5.77 ± 0.0 | 7.85 ± 0.42 | 5.92 ± 0.40 | 7.6 ± 0.47 | 2.08 ± 0.02 | 36.04 | 1.76 ± 0.07 | 29.70 |
| LAPC (cm) | 12.8 ± 1.02 | 17.58 ± 0.81 | 13.2 ± 1.15 | 17.6 ± 0.8 | 4.76 ± 0.21 | 37.12 | 4.38 ± 0.28 | 34.16 |
| MAX DEPTH (cm) | 7.06 ± 0.45 | 9.39 ± 0.41 | 7.11 ± 0.42 | 9.3 ± 0.5 | 2.33 ± 0.04 | 33.0 | 2.21 ± 0.11 | 31.08 |
| MAND DEPTH (cm) | 7.2 ± 0.47 | 9.75 ± 0.45 | 7.26 ± 0.49 | 9.67 ± 0.6 | 2.55 ± 0.02 | 35.4 | 2.41 ± 0.12 | 33.19 |
Abbreviations: AFLA, artificial feeding; EBF, exclusive breastfeeding (direct at‐breast feeding); MF, mixed feeding; SD, standard deviation.
Source: Study dataset.
EBF infants showed greater increases in general growth (weight +136% vs. +120%; length +31% vs. +30%) and craniofacial dimensions, including head circumference, widths, and maxillomandibular depths, compared with MF infants. AF infants exhibited only moderate and variable increments across dimensions; given their very small number (n = 6, 4.9% at T4), they were excluded from transition analyses. (Figure 1).
Significant differences were observed between EBF and MF infants from T1 to T4. Values are presented as mean ± standard deviation, with p values in parentheses corresponding to fixed effects from linear mixed‐effects models. Total craniofacial height was 3.50 ± 0.08 cm in EBF versus 3.25 ± 0.01 cm in MF infants (p = 0.046); anterior facial height, 2.08 ± 0.40 cm vs. 1.76 ± 0.07 (p = 0.016); LAPC, 4.76 ± 0.21 cm vs. 4.38 ± 0.28 (p = 0.005); maxillary depth, 2.33 ± 0.04 cm vs. 2.21 ± 0.11 (p = 0.007); mandibular depth, 2.55 ± 0.02 cm vs. 2.41 ± 0.12 (p = 0.040); head width, 3.31 ± 0.14 cm vs. 2.87 ± 0.37 (p = 0.024); bizygomatic width, 2.28 ± 0.60 cm vs. 2.06 ± 0.50 (p = 0.016); and lower facial width, 2.21 ± 0.04 cm vs. 1.92 ± 0.07 (p = 0.005).
Regarding sagittal and transverse growth, LAPC increased first (EBF 37.12% vs. MF 34.16%), followed by head width (EBF 35.1% vs. MF 29.6%) and head circumference (EBF 22.5% vs. MF 21.2%). Cephalic index (CI) values remained comparable between groups: EBF 73.58 ± 5.48 (T1) and 72.48 ± 4.98 (T4); MF 73.32 ± 5.32 (T1) and 71.42 ± 5.37 (T4). Significant associations were identified between feeding‐related functional variables and specific craniofacial dimensions. A significant interaction between suctions and pauses was observed for ACFT (p = 0.0498). For maxillary depth, a significant effect of exclusive breastfeeding combined with the number of suctions was detected (p = 0.0103). Mandibular depth showed a significant association with the number of pauses (p = 0.0016).
For MAX DEPTH, eight variables were identified as the most significant predictors (p < 0.005), and these are presented in Table 5.
TABLE 5.
Estimated effects of variables associated with (MAX DEPTH growth).
| Explanatory variables | Response variable: MAX DEPTH | |
|---|---|---|
| Estimate effect | p | |
| Age (days) | 0.004054 | < 0.0001 |
| Birth weight (g) | 0.000179 | < 0.0001 |
| Head circumference at birth (cm) | −0.00870 | 0.0374 |
| Male sex (binary: 1 = male, 0 = female) | 0.140 835 | < 0.0001 |
| Current weight (g) | 0.000348 | < 0.0001 |
| PC2 (Maternal health conditions during pregnancy, medication use, vaginal delivery) | −0.04672 | 0.0031 |
| Number of pauses per feeding | 0.010785 | 0.0004 |
| EBF: number of sucks per pause | 0.000254 | 0.0103 |
| Carry‐over effect (transition between feeding types) | 0.037453 | 0.6823 |
Note: Models were fitted using linear mixed‐effects analysis; significant predictors (p < 0.005) are presented.
The carry‐over model was applied to assess potential residual effects of changes in feeding type on craniofacial growth across the study periods. Overall, most dimensions showed non‐significant effects: head circumference and total craniofacial height were negatively affected, while head width showed no effect. Bicigomatic width (coefficient = 0.063; p = 0.247) and maxillary (coefficient = 0.037; p = 0.682) and mandibular depths (coefficient = 0.064; p = 0.471) exhibited positive, non‐significant effects. In contrast, lower facial width increased significantly (coefficient = 0.099; p = 0.0038), and anterior facial height decreased significantly (coefficient = −0.198; p = 0.0151). Both the cephalic and facial indices showed negligible, non‐significant negative effects. These findings indicate that changes in feeding type may have residual effects on specific craniofacial dimensions, although most variables did not reach statistical significance.
Figure 2A illustrates the growth profile of MAX DEPTH from T1 to T4. Infants receiving EBF exhibited a greater increase in MAX DEPTH between T2 and T4 compared to those who did not receive EBF. The steepest growth occurred between T1 and T2, corresponding to infants aged 0–60 days. Figure 2B shows the dispersion of MAX DEPTH values. Infants without EBF displayed greater variability in mean MAX DEPTH between 120 and 180 days, whereas infants with EBF showed values more tightly clustered around the mean throughout the growth curve. After 120 days, the mean MAX DEPTH in EBF infants surpasses that of non‐EBF infants.
FIGURE 2.
Changes in MAX DEPTH (cm) in infants with EBF and non‐EBF between T1 and T4. (A) Growth profile across follow‐up periods T1–T4; (B) Scatter plot of PROFMAX by age with fitted smooth curves and 95% confidence bands. EBF: Exclusive breastfeeding; non‐EBF: Mixed or artificial feeding.
4. Discussion
The methodological design of this research was an analytical longitudinal cohort study aimed at evaluating the effect of craniofacial growth (CCF) in infants aged 0–6 months fed exclusively with breastfeeding (EBF) compared to mixed feeding (MF: maternal + bottle) and artificial feeding (AF: bottle). A total of 202 infants were included: 180 with EBF and 22 with MF. Measurements were conducted across four time points (T1–T4), every two months over six months. At baseline (0–30 days), 89.1% of infants received EBF, decreasing to 52.45% by six months. These figures exceed the most recent global EBF rate of 48% in 2023 and the 50% target set by the World Health Assembly for 2025 [30], but remain below the 70% goal proposed for 2030 by the Global Breastfeeding Collective. This result may partly reflect institutional programs for breastfeeding promotion and maternal motivation to observe changes in their infants at each assessment.
When comparing growth from 0 to 6 months, EBF showed a more stable and continuous pattern, with higher increments in most craniofacial parameters during T1–T2. During T2–T3, a general deceleration occurred; MF infants showed greater head width, while EBF infants retained advantages in facial and mandibular dimensions. In T3–T4, MF surpassed EBF in some transverse dimensions, but EBF maintained higher values in facial height and mandibular depth. These findings suggest that direct breastfeeding supports more harmonious craniofacial growth, whereas MF may accelerate some transverse dimensions later [19, 22, 23].
Differentiated facial growth patterns were observed: in EBF infants, the vertical dimension (AFANT: 36.04%) showed the greatest increase, followed by mandibular depth (35.4%) and transverse growth (Lower Face Width: 28.15%; Bizygomatic Width: 27.4%). In contrast, MF infants exhibited a sequence beginning with mandibular depth (34.16%), followed by AFANT (29.7%) and Bizygomatic Width (24.3%). Previous studies support these findings, reporting that EBF is positively associated with craniofacial growth [5, 7].
Across the follow‐up period (T1–T4), infants in the EBF group showed consistently higher craniofacial measurements than those in the MF group. Statistically significant differences were observed for total craniofacial height, anterior facial height, LAPC, maxillary depth, mandibular depth, head width, bizygomatic width, and lower face width. These differences suggest that breastfeeding suction patterns provide functional stimuli that promote harmonious craniofacial growth across vertical, sagittal, and transverse dimensions [14, 15, 16, 17]. Greater intercanine and intermolar distances in the primary dentition of breastfed children have also been reported [1, 4], supporting the orthopedic function of breastfeeding in promoting balanced maxillomandibular growth through coordinated orofacial muscle activation and tongue positioning [10, 12].
Growth sequences suggest that EBF infants may benefit from more coordinated or efficient oral motor development, supporting functional advantages in feeding, breathing, and swallowing, as suggested by previous studies [19, 20]. These results align with cephalometric studies showing maternal suction generates stronger functional stimuli, particularly in vertical and sagittal dimensions [19]. Thus, feeding types modulate both the magnitude and direction of growth.
Head growth patterns were similar across feeding groups. Longitudinally, LAPC increased earliest, followed by head width and head circumference. EBF infants generally showed slightly greater growth in these dimensions compared with MF infants, while cephalic index values remained similar across groups, suggesting comparable head shape despite differences in growth magnitude. According to Cohen and Maclean [18], CI values between 76.0 and 80.9 indicate mesocephalic, while ≤ 75.9 indicates dolichocephaly. Both groups tended toward dolichocephaly, suggesting breastfeeding contributes to functional stability via coordinated craniofacial muscle movements.
Linear mixed models were applied, allowing assessment of covariate effects on craniofacial outcomes across four repeated measures. Multiple correspondence analysis reduced twelve maternal variables into four principal components explaining 81.9% of total variance. Age at measurement, birth weight, and current weight predict head circumference, head width, bizygomatic width, and lower face width. Male sex influenced craniofacial width, height, and depth, consistent with previous growth studies [14, 22], reflecting genetic potential modulated by feeding type and oral motor function [1, 2, 6].
Our findings suggest that although some craniofacial dimensions were slightly smaller in EBF infants during the first month, growth rapidly adapted, and by T2 these infants matched or exceeded MF infants. This pattern, supported by linear mixed‐effects models, highlights the influence of EBF in combination with functional oral activity. These results indicate that early exclusive breastfeeding promotes favorable craniofacial development, with effects emerging shortly after the initial adaptation period.
Craniofacial structures interact dynamically, responding to signals from the brain, eyes, tongue, and nasal cavity [1, 12, 16, 19]. This study included such influences when analyzing head circumference, head width, and LAPC. A key finding was the relationship between EBF, number of suctions, and pauses, supporting epigenetic theory [1], which posits that feeding type can influence gene expression in craniofacial tissues. Thus, feeding, oral function, and cardiorespiratory activity play critical roles in craniofacial development.
Variables such as Suctions‐Pauses, Age‐EBF, and EBF‐Suctions influenced craniofacial height, AFANT, and bizygomatic width, likely reflecting muscle activity and environmental factors affecting airway and posture [12]. Functional activity during breastfeeding explains skeletal growth patterns, with suction differences between feeding types [11]. Growth profiles also confirmed greater development in EBF infants from T2, reflecting age‐related adaptation and maturation [4, 11].
Residual effects associated with feeding transitions (carry‐over effect) revealed that infants maintaining EBF exhibited stable growth, whereas those transitioning from EBF to MF showed reduced growth magnitude in some craniofacial dimensions. While prior evidence on feeding transitions is limited, studies by Memiş et al. [24] and Güneş et al. [25] provide indirect support. The present study directly evaluated the impact of transitioning from EBF to MF, contributing novel evidence on how feeding transitions influence craniofacial growth.
Mixed feeding represents a heterogeneous exposure, as it may include infants with different durations of exclusive breastfeeding prior to supplementation. To reduce exposure dilution, feeding practices were modeled longitudinally, including a carry‐over term to capture residual effects of prior exclusive breastfeeding across feeding transitions. Future studies may additionally assess exclusive breastfeeding duration as a continuous dose–response exposure.
Exclusive breastfeeding during the first six months appears to promote more harmonious and stable craniofacial growth than mixed feeding, particularly in the early postnatal months. Transition to mixed feeding may exert residual negative effects on certain craniofacial dimensions, while functional variables such as suction–pause patterns significantly influence vertical and sagittal growth. From T2 onward, growth profiles indicated greater craniofacial development in exclusively breastfed infants, reflecting age‐related adaptation and maturation. These findings reinforce the importance of breastfeeding promotion policies and highlight the need for further longitudinal studies incorporating functional assessment of sucking and dynamic analysis techniques to clarify its role in skeletal and orofacial development.
In conclusion, exclusive breastfeeding showed a longitudinal association with greater craniofacial growth between 0 and 6 months of age compared with mixed feeding. Infants who received exclusive breastfeeding presented higher increases in vertical, sagittal, and transverse craniofacial dimensions. These findings indicate that feeding modality is associated with early craniofacial growth trajectories.
Author Contributions
L.Y.G.B., B.V.C., and L.M.H.M. conceived the ideas. L.M.H.M. and B.V.C. collected the patient data. NA. and L.M.H.M. determined the sample sizes. L.Y.G.B. and N.A.C.G. analyzed the data. All authors contributed to the writing of the manuscript.
Funding
The authors have nothing to report.
Ethics Statement
The research was conducted in compliance with the ethical principles outlined in the Declaration of Helsinki (JAMA, 2013) and the International Guidelines for Biomedical Research Involving Human Subjects by CIOMS (2002), which emphasize scientific and social value, ethical review, informed consent, and protection of vulnerable groups. Additionally, the updated CIOMS/PAHO guidelines (2016) for research in resource‐limited settings were applied. The study protocol, as well as the informed consent and assent forms, were reviewed and approved by the Ethics and Research Committee of the health institution (July 18, 2022) and by the Ethics Committee of the Faculty of Nursing at the Universidad Nacional de Colombia (September 16, 2022) (018 Acta 09).
Conflicts of Interest
The authors declare no conflicts of interest.
Acknowledgments
We thank the Facultad de Enfermería of the Universidad Nacional de Colombia for their academic and administrative support throughout all stages of the project. We are grateful to the Ethics Committee of the Subred Norte Hospital de Engativá, Bogotá, Colombia, for their approval and assistance in conducting this research. We also thank the Facultad de Odontología of the Universidad Nacional de Colombia for supporting my doctoral academic training.
Data Availability Statement
The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.