The relationship between exclusive breastfeeding and infant development: A 6- and 12-month follow-up study

What risk factors for Developmental Language Disorder can tell us about the neurobiological mechanisms of language development

Language is a complex multidimensional cognitive system that is connected to many neurocognitive capacities. The development of language is therefore strongly intertwined with the development of these capacities and their neurobiological substrates. Consequently, language problems, for example those of children with Developmental Language Disorder (DLD), are explained by a variety of etiological pathways and each of these pathways will be associated with specific risk factors. In this review, we attempt to link previously described factors that may interfere with language development to putative underlying neurobiological mechanisms of language development, hoping to uncover openings for future therapeutical approaches or interventions that can help children to optimally develop their language skills.

Distinct breast milk microbiota, cytokine, and adipokine profiles are associated with infant growth at 12 months: an in vitro host-microbe interaction mechanistic approach

Breast milk (BM) is important for adequate infant development, and it contains bioactive compounds, such as bacteria, cytokines and some adipokines which play a role in infant microbial, metabolic, and immunological maturation. However, little is known about its impact on growth and development in early life. The objective of this study was to evaluate the impact of milk microbiota, cytokine, and adipokine profiles on the risk of overweight at 12 months of life to find the possible mechanisms of host-microbe interactions. In this study, BM samples from 100 healthy women collected during 15 d after birth were included. BM microbiota was analysed by 16S rRNA gene sequencing, and cytokine and adipokine levels were measured by the Luminex approach. In addition, infant weight and length were recorded during the first 12 months and z-scores were obtained according to the WHO databases. Infants were classified as risk of overweight (ROW) and no-risk of overweight (NOROW) based on their body mass index z-score (BMIZ) and infant weight-for-length z-score (WLZ) at 12 months. In order to study host-microbe interactions, epithelial intestinal and mammary cell lines were exposed to milk microbes to assess the host response by interleukin (IL)-6 production as a potential inflammatory marker. BM was dominated by Staphylococcus and Streptococcus genera, and the most abundant cytokines were IL-6 and IL-18. Leptin levels were positively correlated with the pregestational body mass index (BMI). Higher relative abundance of the Streptococcus genus was associated with higher IL-10 and higher relative abundance of the Bifidobacterium genus was associated with lower IL-6 concentrations in milk. Infant WLZ at 12 months could be partially predicted by Streptococcus genus proportions and IL-10 and IL-18 levels in BM. BM microbiota significantly induced cytokine responses in mammary epithelial cells. Higher levels of IL-6 production were observed in mammary cells exposed to BM microbiota from mothers with ROW offspring compared to mothers with NOROW offspring. In conclusion, BM microbiota is related to the cytokine profile. IL-10 and IL-18 levels and the abundance of the Streptococcus genus could affect early infant development. Further research is needed to clarify the specific impact of BM microbiota and cytokines on infant growth and the risk of overweight.

Searching for a Relationship between Early Breastfeeding and Cognitive Development of Attention and Working Memory Capacity

Previous research consistently reported that subjects that were exclusively breastfed (eBF) vs. not-exclusively breastfed (neBF) during infancy (0-6 months) showed increased scores of general intelligence measures (e.g., the intelligence quotient). However, the existent literature largely neglected whether breastfeeding also affects specific cognitive processes, such as attention and working memory (WM) capacity. We tested whether eBF vs. neBF subjects showed performance differences in relation to these two core cognitive functions. The Attention Network Test (ANT), to measure alerting, orienting, and conflict, and the Change Colour Task (CCT), to measure visuospatial WM capacity, were administered to 144 participants divided according to age (6-, 10-, and 18-year-old participants) and breastfeeding (eBF or neBF during 0-6 months of life). Importantly, the sub-groups were homogenous in terms of maternal education, a factor potentially affecting the relation between breastfeeding and cognition. While we found increased performance as a function of participants' age in both tasks, we failed to observe effects related to breastfeeding, as evidenced by Bayesian analyses. These findings highlight for the first time that the pattern of nutrition provided during early infancy does not appear to affect the development of attention and WM capacity, at least starting from the age considered in the present study.

Early Life Beef Consumption Patterns Are Related to Cognitive Outcomes at 1–5 Years of Age: An Exploratory Study

Protein, iron, zinc, and choline affect early brain development and are found in beef. The aims of this study were to describe (1) early feeding practices related to introduction of beef in the rural US west (Idaho); (2) parental perceptions of beef as a first food, and (3) associations between early beef consumption and child cognition at 1–5 years. A total of 61 children and their parents were enrolled. Parents completed a survey and a food frequency questionnaire to assess perceptions of beef and early feeding practices along with their child’s dietary intake at 6–12 months. Children’s cognitive function was assessed using the Bayley-4 Scales of Infant and Toddler Development (12–35 months) and the NIH Toolbox for Assessment of Neurological and Behavioral Function (NIHTB) (3–5 years). Parents introduced beef at 7.79 ± 2.65 months of age, primarily so that their children could eat what the family was eating. Higher intake of beef (r = 0.41, p = 0.02), zinc (r = 0.45, p = 0.01), and choline (r = 0.39, p = 0.03) at 6–12 months was associated with better attention and inhibitory control at 3–5 years of age. These findings support the role of beef as an early food for cognitive development, although controlled dietary intervention studies are needed.

Breastfeeding duration and vagal regulation of infants and mothers

BACKGROUND

Vagal regulation within the parasympathetic nervous system supports self-regulation and social engagement. Research has suggested that early feeding practices may influence mother-infant vagal functioning.

AIM

We aimed to examine the association between breastfeeding duration and mother-infant vagal regulation during an interaction. We hypothesized that breastfeeding duration would be positively associated with adaptive vagal regulation in infants and mothers.

METHOD

204 mother-infant dyads (infant mean age 6 months) completed the face-to-face still-face (FFSF) task. During the task, vagal regulation indexed by respiratory sinus arrhythmia (RSA, a component of heart rate variability) was calculated through continuously recorded electrocardiogram signals. Breastfeeding duration and demographic information were reported by mothers. Linear mixed models were adopted to estimate the associations between breastfeeding duration and repeated measures of RSA in infants and mothers throughout the FFSF.

RESULTS

Infants breastfed for a longer duration demonstrated lower RSA throughout the FFSF (B = -0.06, 95 % CI: -0.09 to -0.03), suggesting active physiological mobilization to engage in interaction and regulate distress. Mothers with longer breastfeeding duration displayed higher baseline RSA and higher overall RSA levels (higher vagal control) during the FFSF (B = 0.06, 95 % CI: 0.02 to 0.09), indicating a calmer and regulated state.

CONCLUSION

Longer breastfeeding duration was associated with more adaptive mother-infant vagal regulation during the interaction, indicating a positive dose-response association. This finding reveals breastfeeding practice as a factor contributing to infant effective vagal regulation and further supports WHO recommendation on exclusive breastfeeding for the first 6 months and continuing breastfeeding to 24 months and beyond.

The Effects of Breastfeeding on Maternal Mental Health: A Systematic Review

Background: Breastfeeding has many positive effects on the health of infants and mothers, however, the effect of breastfeeding on maternal mental health is largely unknown. The goal of this systematic review was to (1) synthesize the existing literature on the effects of breastfeeding on maternal mental health, and (2) inform breastfeeding recommendations. Materials and Methods: A literature search was conducted in electronic databases using search terms related to breastfeeding (e.g., breastfeeding, infant feeding practices) and mental health conditions (e.g., mental illness, anxiety, depression), resulting in 1,110 records. After reviewing article titles and abstracts, 339 articles were advanced to full-text review. Fifty-five articles were included in the final analysis. Results: Thirty-six studies reported significant relationships between breastfeeding and maternal mental health outcomes, namely symptoms of postpartum depression and anxiety: 29 found that breastfeeding is associated with fewer mental health symptoms, one found it was associated with more, and six reported a mixed association between breastfeeding and mental health. Five studies found that breastfeeding challenges were associated with a higher risk of negative mental health symptoms. Conclusions: Overall, breastfeeding was associated with improved maternal mental health outcomes. However, with challenges or a discordance between breastfeeding expectations and actual experience, breastfeeding was associated with negative mental health outcomes. Breastfeeding recommendations should be individualized to take this into account. Further research, specifically examining the breastfeeding experiences of women who experienced mental health conditions, is warranted to help clinicians better personalize breastfeeding and mental health counseling.

Associations between exclusive breastfeeding duration and children's developmental outcomes: Evidence from Siaya county, Kenya

BACKGROUND

Exclusive breastfeeding (EBF) during the first 6 months of life is widely promoted as a key strategy to enhance child health, growth, and development. Even though a high proportion of children in Kenya are currently breastfed exclusively, there is little evidence regarding the developmental benefits during the first year of life. This paper aims to fill this gap by establishing an association between EBF and early childhood developmental outcomes among children below the age of 6 months in Kenya.

METHODS

We used data collected as part of a cluster-randomized controlled trial conducted in Bondo sub-county in the western part of Kenya to assess the associations between EBF and development in the first year of life. The primary exposure variable was EBF, and the outcome variable was child development as measured by the Ages and Stages Questionnaire-Third Edition (ASQ-3).

RESULTS

We analyzed data from 570 children aged below 6 months at the time of the interview. Breastfeeding children exclusively between 3 and 6 months was associated with 0.61 standard deviation (SD) higher ASQ-3 scores in the adjusted model. When specific domains were considered, in the adjusted models, EBF in the 3-6 months period was associated with 0.44 SD, 0.34 SD and 0.36 SD higher ASQ-3 scores in communication, gross motor, and problem solving domains, respectively. There were weak associations in the fine motor and social-emotional domains.

CONCLUSION

EBF in the 3- to 6-month age range has significant positive associations with child development, especially for communication, gross motor, and problem-solving. Programs encouraging mothers to continue EBF in this period may have substantial benefits for children.

Cohort profile: National Investigation of Birth Cohort in Korea study 2008 (NICKs-2008)

BACKGROUND

An adequate large-scale pediatric cohort based on nationwide administrative data is lacking in Korea.

PURPOSE

This study established the National Investigation of Birth Cohort in Korea study 2008 (NICKs-2008) based on data from a nationwide population-based health screening program and data on healthcare utilization for children.

METHODS

The NICKs-2008 study consisted of the Korean National Health Insurance System (NHIS) and the National Health Screening Program for Infants and Children (NHSPIC) databases comprising children born in 2008 (n=469,248) and 2009 (n=448,459) in the Republic of Korea. The NHIS database contains data on age, sex, residential area, income, healthcare utilization (International Classification of Diseases-10 codes, procedure codes, and drug classification codes), and healthcare providers. The NHSPIC consists of 7 screening rounds. These screening sessions comprised physical examination, developmental screening (rounds 2-7), a general health questionnaire, and age-specific anticipatory guidance.

RESULTS

During the 10-year follow-up, 2,718 children (0.3%) died, including more boys than girls (hazard ratio, 1.145; P<0.001). A total of 848,048 children participated in at least 1 of the 7 rounds of the NHSPIC, while 96,046 participated in all 7 screening programs. A total of 823 infants (0.1%) weighed less than 1,000 g, 3,177 (0.4%) weighed 1,000-1,499 g, 37,166 (4.4%) weighed 1,500-2,499 g, 773,081 (91.4%) weighed 2,500-4,000 g, and 32,016 (5.1%) weighed over 4,000 g. There were 23,404 premature babies (5.5%) in 2008 compared to 23,368 (5.6%) in 2009. The developmental screening test indicated appropriate development in 95%-98% of children, follow-up requirements for 1%-4% of children, and recommendations for further evaluation for 1% of children.

CONCLUSION

The NICKs-2008, which integrates data from the NHIS and NHSPIC databases, can be used to analyze disease onset prior to hospitalization based on information such as lifestyle, eating habits, and risk factors.

Language abilities in children born to mothers diagnosed with diabetes: A systematic review and meta-analysis

BACKGROUND

This meta-analysis reviewed and synthesized the available evidence on the association between intrauterine exposure to maternal diabetes and language abilities in children.

METHOD

MEDLINE/PubMed, EMBASE, PsycINFO, Proquest Dissertations and Theses Global, and Google Scholar databases were searched through December 2020. Studies were systematically searched, and effect sizes were calculated using random effects models.

RESULTS

Twelve studies were identified for inclusion in this review, however, only 10 were included in the meta-analysis. Sample size ranged from 9 to 115 participants in the diabetes group and 28 to 8192 in the control and aged around 3 years. The pooled results of the meta-analysis showed a trend of decreased language abilities in receptive (z = -3.49, df = 10, I² = 34, p = 0.001), expressive language development (z = -2.29, df = 11, I² = 94%, p = 0.022) and general communication (z = -4.12, df = 4, I² = 2, p = 0.001) However, results showed a limited effect of maternal diabetes on children's language abilities after excluding high-risk categories such as children born to mothers with other gestational comorbidities, obesity and low socio-economic status.

CONCLUSION

Our meta-analysis recognises that exposure to maternal diabetes during pregnancy intersects with other factors within the intrauterine environment to create the conditions for reduced language abilities in the child. Multiple factors may contribute to the observed differences between groups in the meta-analysis. A focus on interventions to maintain optimal blood glucose levels during pregnancy and to screen for early developmental delay after birth is recommended.

Baby-led weaning in Italy and potential implications for infant development

Baby-led weaning is an approach to complementary feeding that emphasizes an infant's ability to self-feed rather than being spoon fed, and to eat minimally-processed foods rather than puréed foods. This study aimed to investigate the variability in infant feeding practices and the possible association with developmental milestones in an Italian population. A sample of 1245 mothers of 6-12 month-old infants completed an online survey about complementary feeding and their infant's attainment of developmental milestones. Infants' eating of family food was positively related to self-feeding and to a lower consumption of puréed foods. As in previous studies in the UK and New Zealand, a baby-led weaning style was positively associated with breastfeeding, exposure to complementary foods around six months of age, earlier exposure to both finger and family foods, and higher interest in family food and shared family meals. Infants who were introduced to solid foods using a baby-led weaning approach were more likely to have met important developmental milestones; when controlling for covariates, percentage of family feeding was positively associated with sitting unsupported at an earlier age and a low spoon-feeding style was associated with crawling at an earlier age. These data suggest that baby-led weaning should be defined more comprehensively. Moreover, its potential influence on developmental domains beyond diet and eating behavior warrants future targeted exploration.

Breastfeeding practices after a counselling intervention for factory workers in Bangladesh

Breastfeeding may be particularly challenging for female factory workers who have long working hours and inadequate access to health information and care. In Chattogram, Bangladesh, a peer counselling intervention was undertaken to improve infant feeding practices of factory workers. Counselling started during pregnancy and continued until children were 18 months old. This article presents the results of a cross‐sectional survey undertaken during 2 weeks in March–April 2017, after the project's conclusion. The aim was to compare breastfeeding practices, specifically early breastfeeding initiation and exclusive breastfeeding (EBF), among factory workers who had received peer counselling in the intervention areas (IA) with those of non‐counselled factory workers in the nearby comparison areas (CA). Six female interviewers, trained over 3 days, conducted interviews at the workers' homes. Data were analysed to assess the association of peer counselling with infant feeding practices. Factory workers (N = 382) with infants between 0 and 18 months of age participated in the survey, in IA (n = 188) and in CA (n = 194). Although there were more health facility deliveries among the CA workers, only 43 (22%) of those workers had initiated breastfeeding within 1 h of birth versus 166 (88%) of the IA workers (p < .001). EBF prevalence on 24‐h recall in infants aged 0–6 months was only 7/83 (8%) for the CA workers versus 73/75 (97%) for IA workers (p < .001). The survey showed that breastfeeding practices of factory workers in the IA after the intervention were significantly better than those of factory workers in the CA.

The Possible Effects of Breastfeeding on Infant Development at 3 Months: A Case-Control Study

Objective: To examine the influence of exclusive breastfeeding on infant development among 3-month-old infants in a Chinese population. Methods: Mothers and their 3-month-old infants were recruited from four maternal and child health hospitals from April 2018 to March 2019. Based on the infants' feeding patterns, the mother-infant dyads were divided into two groups: exclusive breastfeeding and formula feeding groups. Infant development was evaluated using the Chinese version of the Ages and Stages Questionnaires, 3rd edition (ASQ-C), and maternal depression, parenting confidence, and infant temperament were also assessed using the relevant scales/questionnaires. Multivariate logistic regression analysis was conducted to explore the effects of feeding patterns on infant development at 3 months. Results: The data from 417 mother-infant dyads were analyzed. For the breastfeeding group and formula feeding group, the risk of developmental delay measured by the ASQ-C was 4.1% (10/244) and 9.3% (16/173) respectively for the communication domain; 5.7% (14/244) and 8.1% (14/173) for problem-solving domain and 6.2% (15/244) and 12.1% (21/173) for personal-social domain, respectively. Compared with exclusive breastfeeding, formula feeding was a risk factor for delayed development of communication (adjusted odd ratio [aOR] = 2.60, 95% confidence interval [CI] = 1.42-4.75) problem-solving (aOR = 1.91, 95% CI = 1.06-3.45), and personal-social skills (aOR = 1.96, 95% CI = 1.12-3.42). Conclusions: Exclusive breastfeeding is important for infant communication, problem solving, and social interaction at the age of 3 months. Formula-fed infants may be at a higher risk of developmental delay than exclusively breast-fed infants. It is necessary to encourage mothers to establish and continuous breastfeeding.

Developmental assessments during the first 5 years of life in infants fed breast milk, cow's milk formula, or soy formula

OBJECTIVE

To investigate the effects of infant feeding mode on childhood cognition and language as the differential effects of infant feeding on development remain understudied.

METHODS

Breastfed [BF, 174], cow's milk-based formula-fed [MF, 169], or soy protein-based formula-fed [SF, 161] children were longitudinally tested from age 3 to 60 months for neurodevelopment. Data were analyzed using mixed models while adjusting for multiple covariates. Sex differences were also assessed.

RESULTS

Standard scores were within established norms for all groups. There were no differences in mental development to age 24 months, yet BF children had significantly higher motor development scores at age 3 months than SF children (99.1 versus. 97.2). BF children had significantly higher composite intelligence scores at 48 months than MF and SF children (113.4 versus. 109.6 and 108.4, respectively) and higher verbal intelligence scores than SF children at 48 (105.6 versus. 100.7) and 60 months (109.8 versus. 105.9). Greater total language scores at ages 36 and 48 months were found in BF children compared with children fed MF or SF (p < .001), with differences between sexes for auditory comprehension. Higher total language scores at age 60 months were found between BF and SF (105.0 versus. 100.1).

CONCLUSION

Breastfeeding was associated with small, statistically significant, differences between children ages 3 and 5 years in verbal intelligence, expressive communication, and auditory comprehension with the latter having potential sexual dimorphic effects. Yet, these differences remain small and may not be of clinical relevance. Overall, MF and SF did not significantly differ.

Breastfeeding Behavior in Brazilian Children with Congenital Zika Syndrome

Congenital Zika Syndrome (CZS) is a condition that has emerged only recently, bringing together multiple changes, including significant changes in the stomatognathic system, which may compromise sucking behavior and consequently the breastfeeding practice. The aim of this study was to investigate the breastfeeding behaviors in children with CZS. A longitudinal study was carried out in two reference centers in Northeastern Brazil. The nonprobabilistic sample consisted of 79 children diagnosed with physical, neurological, and behavioral alterations compatible with CZS. Information regarding the child, nutritive, and nonnutritive sucking behavior and changes related to the sucking reflex was collected. Data were presented through descriptive and inferential statistics. In the bivariate analyses, the chi-squared test was used and 5% significance level was adopted. The majority of children had severe microcephaly (59.7%). Breastfeeding was performed at birth in most of CZS children (89.9%) but only 36.6% of them presented exclusive breastfeeding in the six months of life. Bottle feeding and pacifier were used in 89.9% and 55.7%, respectively. Sucking and swallowing difficulties and occurrence of gastroesophageal reflux were observed in 27.8%, 48.0%, and 29.2% of children, respectively. Early weaning was associated with bottle feeding (p=0.005) and pacifier sucking (p=0.003). Although breastfeeding practice at birth constitutes a behavior adopted by most of mothers, adherence to this exclusive habit until the first six months of life was low since the children presenting a large number of comorbidities with direct interference in the suction reflex, sucking, and swallowing difficulty.

Maternal Health and Nutrition Status, Human Milk Composition, and Growth and Development of Infants and Children: A Prospective Japanese Human Milk Study Protocol

It is unknown whether maternal health and nutrition are related to human milk composition or growth and development of infants and children. Here, we describe a protocol for a prospective five-year cohort study to clarify (i) how maternal health and nutrition, socioeconomic factors, and lifestyles affect human milk composition, and (ii) whether these are associated with growth and development of infants and children. In our study, we recruited 1210 Japanese mothers with singleton pregnancies from 73 obstetrics clinics and hospitals across Japan, between 2014 and 2019. We will measure the following: health information regarding maternal-child dyads using a self-administered questionnaire, maternal nutrition during breastfeeding using a Brief self-administrated Diet History Questionnaire, the development of infants and children using the Kinder Infant Development Scale, and the stress related to child rearing using the Mother’s Child Care Stress Scale. Simultaneously, we will collect human milk every 2 months during the first year after birth to measure its composition and levels of macronutrients. This study will generate useful data to investigate whether health status, nutritional status, lifestyle, and socioeconomic factors affect human milk composition and the growth and development of infants and children.

Bermúdez M, Campoy C. Influence of a Functional Nutrients-Enriched Infant Formula on Language Development in Healthy Children at Four Years Old

Nutrition during early life is essential for brain development and establishes the basis for cognitive and language skills development. It is well established that breastfeeding, compared to formula feeding, has been traditionally associated with increased neurodevelopmental scores up to early adulthood. We analyzed the long-term effects of a new infant formula enriched with bioactive compounds on healthy children's language development at four years old. In a randomized double-blind COGNIS study, 122 children attended the follow-up call at four years. From them, 89 children were fed a standard infant formula (SF, n = 46) or an experimental infant formula enriched with functional nutrients (EF, n = 43) during their first 18 months of life. As a reference group, 33 exclusively breastfed (BF) were included. Language development was assessed using the Oral Language Task of Navarra-Revised (PLON-R). ANCOVA, chi-square test, and logistic regression models were performed. EF children seemed to show higher scores in use of language and oral spontaneous expression than SF children, and both SF and EF groups did not differ from the BF group. Moreover, it seems that SF children were more frequently categorized into "need to improve and delayed" in the use of language than EF children, and might more frequently present "need to improve and delayed" in the PLON-R total score than BF children. Finally, the results suggest that SF children presented a higher risk of suffering language development than BF children. Secondary analysis also showed a slight trend between low socioeconomic status and poorer language skills. The functional compound-enriched infant formula seems to be associated with beneficial long-term effects in the development of child's language at four years old in a similar way to breastfed infants.

Effect of feeding patterns on growth and nutritional status of children aged 0-24 months: A Chinese cohort study

Objective

This study was aimed to examine the effect of feeding patterns on growth and nutritional status of children aged 0~24 months.

Methods

We conducted a cohort study with an initial sample of 927 children. Considering the follow-up losses, 903, 897, 895, 897, 883, 827 and 750 children were followed up at 1, 3, 6, 8, 12, 18 and 24 months, respectively. Children were grouped according to exclusive breastfeeding (EBF) duration in the first 6 months: (1) never EBF; (2) EBF ≤ 3 months: EBF ≤ 3 months and stopped BF after 3 months or EBF ≤ 3 months and BF = 6 months or EBF ≤ 3 months and BF after 3 months, had formula and/or solids; (3) EBF for 3 ~ 6 months: BF < 3 months and EBF for 3 ~ 6 months or EBF for 3 ~ 6 months and BF < 3 months, had formula and/or solids; (4) EBF = 6 months. We used Z-scores to evaluate the growth and nutritional status of children, used the generalized estimation equation to compare the difference between feeding patterns.

Results

The generalized estimation equation results showed that Weight-for-age Z-score (WAZ), Length-for-age Z-score (LAZ), and Weight-for-length Z-score (WLZ) in different feeding patterns had statistical significance. The WAZ in EBF for 6 months group was higher in the first 8 months, in never EBF group was higher after 12 months old; the LAZ in EBF for 6 month group was lower than other groups; the WLZ in EBF for 6 months group was higher than EBF for 3 ~ 6 months group. The EBF ≤ 3 months group had higher underweight, stunting, and wasting rates. The EBF for 6 months had a higher stunting rate; the never EBF and EBF for 6 months groups had higher overweight and obesity rates.

Conclusions

In conclusion, different feeding patterns affect growth and nutritional status in children, so proper guidelines should be implemented to improve nutritional status and promote the growth of children.

Drugs in lactation

Although most medications can be taken safely during breastfeeding, potential risks of infant toxicity do exist because all medications will be excreted into the breast milk to some extent. The amount of medication excreted in the milk depends mainly on (i) within-drug variation, such as dosing; (ii) between-drug variation including chemical characteristics of the medication; and (iii) host factors, such as maternal pharmacokinetics (PK), including variations of pregnancy-associated changes and their post-partum recovery. Neonatal drug exposure is usually assessed by calculating an expected total infant daily dose through breast milk and comparing it to the normal therapeutic dose. However, clinical PK studies in this population are challenging to conduct. Recently, research methods using population PK analyses and physiologically-based PK modeling and simulation techniques have been recognized as a complementary approach to the conventional PK studies in this field. These efforts are important for rational risk assessment balancing the toxicity risk against the benefits of human milk. Health benefits of lactation for both mother and child are significant and a decision to withhold from this should not be taken lightly. In case limited information is present, additional expertise from pharmacists or clinical pharmacologist with expertise in this area should be sought.