The literature review focuses on the studies based on the developmental effects of breastfeeding, the effect of breastfeeding in supporting the motor and cognitive development, and the implications of lack of breastfeeding. The sources of information for the review were obtained from online databases, including PsycINFO, Google Scholar, Ebscohost, and MedlinePlus. The literature search provided hundreds of articles relating to the keywords. However, only 25 sources were included in the review because they met the basic criteria, such as the language of publication (English), year of publication (2013-2019), and the relevance of the discussion topics, breastfeeding and development. The review includes various sections related to the topic of study, including effect of breastfeeding on child development, impact on motor and cognitive development, the implications of breastfeeding (including the adverse effects of failure to breastfeed), gaps in research, and summary.
The Effect of Breastfeeding on Child Development
The role of breastfeeding in the development of children has remained a subject of major empirical research for decades. Researchers seek to understand the complex association between breastfeeding and various areas of a child’s development. For various reasons, determining the actual relationship between breastfeeding and child development is challenging. For example, various maternal and child factors affect the relationship between the variables. However, researchers have explored the influence of breastfeeding and the duration on intelligence quotient (IQ), psychomotor, and social development on babies during their early days and later in life (Tasnim, 2014). The researcher suggested that children who are breastfed tend to have a higher IQ compared to those who are not breastfed.
The Effect of Breastfeeding on Cognitive and Motor Development
Questions arise as to whether breastfeeding has any effect on early brain development. Current research evidence appears to point to a potential effect of early exclusive breastfeeding on improvement in cognitive development, such as a high IQ, during later childhood and teenage. Deoni et al. (2013) suggested that children who are breastfed tend to have higher white matter development compared to those who lack breastmilk. The positive development is revealed in various parts of the brain that affects cognitive and behavioral performance measures. The results suggested a potential connection between breastfeeding and development in the parts of the brain that influence intelligence. However, the study lacked evidence of the mechanisms that underly the structural disparities in children who are breastfed and those who are not breastfed.
Further studies explored the actual connection between breastfeeding and cognitive development. In a follow-up study, Lee et al. (2016) investigated the relationship between breastfeeding and cognitive development. The scholars followed the development of infants during their first three years of life. The research conducted as part of Mothers’ and Children’s Environmental Health (MOCEH) project revealed a positive connection between breastfeeding duration and mental development index score. The study showed that the use and duration of breastfeeding had a positive relationship with cognitive development in children. In a comparative analysis, Lee et al. (2016) found out that children who breastfed for ≥ 9 months had a better mental development index score compared to those who had not breastfed. Other studies have revealed a small but significant effect of breastfeeding on intelligence quotient (von Stumm & Plomin, 2015). The study concluded that breastfeeding has little, but significant advantage for the development of cognition and intelligence during early life.
Studies that used other methodologies provided other relevant evidence to comprehend the role of the developmental implications of breastfeeding. Horta, Loret de Mola, and Victora (2015) conducted a review of the literature to find out whether a connection exists between breastfeeding and performance in intelligence assessments. In their review of 17 studies, the researchers established that breastfeeding was connected to improvement in performance in intelligence assessments. Similar to the study conducted by Lee et al. (2016), the review found a strong positive connection between breastfeeding and cognitive development. Adjusting for covariates, research reveals that children who are breastfed have higher scores in cognitive development (Huang, Peters, Vaughn, & Witko, 2014). The study discovered an essential association between breastfeeding and cognitive development. Besides, schooling during childhood and adolescence does not eliminate the difference in cognitive development between children who are breastfed and those who are not. Cognitive development during early childhood plays a vital role in intelligence throughout a person’s life.
Research provides the benefits of exclusive breastfeeding during the first months of a child’s life. Breastfeeding a child for three months or more, was found to have a positive relationship with the child’s readiness for learning, such as the development of language skills (Gibbs & Forste, 2014). However, besides breastfeeding, the study identified the role of cognitive-supportive parenting behaviors and high level of education among mothers who breastfeed their children. With less educated mothers, the effect of breastfeeding on cognitive development was found to be minimal. The research appears to support the role of the mother as well as other critical parental factors, such as education and IQ, in achieving positive cognitive development in children. Therefore, mothers should understand the crucial role of breastfeeding to realize optimum developmental benefits.
Other developmental benefits of breastfeeding related to cognition are evident in research. Besides the effect of breastfeeding on cognitive development, Iqbal, Rafique, and Ali (2017) investigated the impact on the language development of children. They explored the relationship between breastfeeding and both cognitive and language development. In their secondary data-analysis based on “Balochistan – Early Childhood Development Project,” the researchers established that children breastfed for over 12 months experienced benefits in terms of the development of the two areas. They concluded that the duration in which the child is breastfed plays a positive role in cognitive and language development. They recommended policies to promote breastfeeding for more than 12 months to achieve optimal growth. Policy-makers can use the information to promote proper breastfeeding and relevant duration to promote cognitive benefits.
Researchers assumed unique approaches to the study of the effect of breastfeeding on children. Pang et al. (2019) took a somewhat different approach from other researchers to establish the connection between nutrition and cognitive development. The researchers explored the relationship between the mode of milk feeding (nursing) and the type of milk feeding (the nutrients) on cognitive development in the baby. The results of their study indicated that children who were bottle-fed breast milk had better performance on cognition compared with those who were fed formula milk only. The research supported other studies, such as Lee et al. (2016), which found a strong connection between nutrients in breast milk and cognitive development. The study adds to the body of knowledge that affirms the positive effect of breastfeeding.
Besides cognitive development, studies revealed other areas that benefit from optimal breastfeeding. Leventakou et al. (2015) investigated the relationship between breastfeeding and three developmental outcomes, including cognitive, language, and motor skills. Their study applied data from the prospective mother-child cohort (‘Rhea’ project) to establish the relationship between the variables. In their research, they confirmed that the breastfeeding duration had a linear relationship with cognitive, language, and motor development. Similar to the results by Iqbal, Rafique, and Ali (2017), Leventakou et al. (2015) revealed that longer duration of breastfeeding improves scores in cognitive, language, and motor development. Hence, the results applied to children by the age of 18 months of age, independent of infant and parental characteristics.
While some of the studies revealed a positive connection between breastfeeding and various developmental variables, others found conflicting results. In a systematic review of previous studies, Walfisch, Sermer, Cressman, and Koren (2013) had earlier revealed conflicting results regarding the relationship between breastfeeding and cognitive development. They established that the studies had contradictory findings, including null and positive effects. However, they concluded that the conflicting results could be due to confounding factors relating to breastfeeding, such as maternal socio-economic status and intelligence quotient. The researchers suggested that due to the effects of the confounders, future research should attempt to control such factors to acquire more reliable results.
Research on the long-term effects of breastfeeding on cognition is also critical. Unlike other studies that focused on the impact of breastfeeding on intelligence in the short-term (Leventakou et al., 2015; Iqbal, Rafique, & Ali, 2017), Victora et al. (2015) investigated the long-term consequences of breastfeeding. Their study focused on whether the duration of breastfeeding was connected with IQ, the period of schooling, and income by the time a person is 30 years. They focused on the educational attainment and participant’s income by 30 years of age. The study indicated that IQ affected the level of income and that breastfeeding was connected to enhanced performance in intelligence tests three decades later. They concluded that breastfeeding might have significant implications in real-life by affecting educational attainment and the level of income.
Other studies were performed to establish the effect of breastfeeding on motor development. Michels et al. (2017) conducted their research to find out the effect of breastfeeding on motor development. The study differed from others, such as Leventakou et al. (2015) that investigated the connection between breastfeeding and motor development among other variables, such as cognitive development. However, their study failed to find statistically significant evidence of a relationship between the variables, even in preterm babies.
Besides the cognition and motor skills development, some studies took a broader view of the implication of breastfeeding. Stelmach et al. (2019) explored the effect of breastfeeding on neurodevelopment. The authors based their study on the Polish Mother and Child Cohort Study, which investigated the relationship between breastfeeding duration and neurodevelopment in children, controlling for maternal age and BMI, weight gained during pregnancy, maternal education, and the gender of the child among other factors. The results indicated that the breastfeeding duration did not have a significant relationship with the development of a child. The study suggested that other factors, such as the age of the parent and educational level might determine neurodevelopment in the child, such as IQ level.
Further research revealed similar implications. A related study was conducted earlier by Julvez et al. (2014) to establish the role of breastfeeding duration on neuropsychological development. The study sought to find out other possible factors that determine the effect, such as familial social, psychological, and nutritional forces. Their research revealed that complete breastfeeding had an independent relationship with the McCarthy Scales of Children’s Abilities scores. Therefore, although maternal factors, such as social class, education, and intelligence, were essential aspects of the neuropsychological performance of the child, breastfeeding remained an important determinant.
Other Developmental Benefits of Breastfeeding
Besides the effect on cognitive and motor development, researchers have identified other advantages of breastfeeding. McCrory and Murray (2013) investigated the association between breastfeeding and neurodevelopment at 9 months. Their study revealed positive effects of breastfeeding on various development areas, such as fine motor, gross motor, problem-solving, and personal-social capabilities. However, their study failed to establish a clear relationship between breastfeeding and the development of communication skills. Belfort et al. (2016) also explored other areas of development that breastfeeding may affect children. They examined the relationship between the duration and exclusivity of breastfeeding and development in behavior, executive function, and social-emotional aspects. However, unlike other studies, such as McCrory and Murray (2013) that revealed a positive connection, the research did not reveal any substantial association between the variables. The authors established that children who are exclusively breastfed for an extended period do not necessarily rate well in terms of their behavior, executive function, and social-emotional capabilities. They did not find any improvement for each additional month of exclusive breastfeeding. The study lacks conclusive evidence of the positive effect of breastfeeding on behavior, executive function, and social-emotional areas.
Further research explored the relationship between breastfeeding and general psychological development. Krol and Grossmann (2018) examined the role of breastfeeding on positive psychological outcomes on mothers and children. Breastfeeding allows the supply of optimal nutritional benefits from the mother to the baby. Therefore, breastfeeding is the optimal source of nutrients necessary for positive postnatal life. Research shows that besides being the primary source of nutrition for babies, breastfeeding is positively related to other positive outcomes, such as development in cognition, behavior, and mental health. Krol and Grossmann (2018), in their review of previous research, revealed the neurobiological mechanisms underlying the positive psychological effect of breastfeeding on the mother and child, such as nutritional intake. The study supports a potential association between breastfeeding and psychological development.
The Implications of Breastfeeding
The implications of breastfeeding on child development relate to the positive impact of breastfeeding and the detrimental effect of failure to breastfeed. McCrory and Murray (2013), in their study of Irish children, found that children who were never breastfed had delayed milestones. Compared to children who were exclusively or partly breastfed, children who were not breastfed reached various milestones later in life. However, Huang, Peters, Vaughn, and Witko (2014) revealed no differences between children who are breastfed and those who are not in terms of growth trajectories in cognitive assessment scores over time. The study by Colen and Ramey (2014) suggested that the relationship between breastfeeding and the health of the baby might not exist per se. Many of the beneficial long-term effects of breastfeeding might be caused by other factors, such as demographic characteristics and feeding practices. Their study failed to reveal any actual positive or detrimental effects of breastfeeding on children.
However, some researchers confirm the beneficial effect of breastfeeding. Regardless of the findings by Colen and Ramey (2014), Park et al. (2014) established a positive relationship between breastfeeding and lower risk of behavioral issues in children. They explored the role of breastfeeding as a protective factor in the development of attention-deficit hyperactivity disorder (ADHD) and similar problems in children. Their research showed that lack of breastfeeding created the risk of internalizing, externalizing, and general behavioral issues in children. It also increased the possibility of developing ADHD. Therefore, the research revealed a protective effect of breastfeeding on the studied variables. The study affirmed earlier findings by Mimouni-Bloch et al. (2013) that found the potential of breastfeeding to prevent ADHD. Given the role of breastfeeding in physical and mental development, it might be negatively associated with the risk of neurobehavioral disorders, such as ADHD (Bloch et al., 2013). The study comparing the length of breastfeeding, at 3 months and 6 months, revealed that children with a longer duration of breastfeeding have a lower risk of ADHD.
Research indicates the protective role of breastfeeding. In another study, Liu, Leung, and Yang (2014) elucidated the role of breastfeeding and mother-child interactions on the child. The research established that breastfed children, as well as those with actively engaged mothers, had a lower risk of developing internalizing issues. Conversely, children who were not exclusively breastfed and with inadequate bonding with their mothers lacked the protection against the negative behaviors. Overall, Dieterich, Felice, O’Sullivan, and Rasmussen (2013) suggested that breastfeeding is beneficial to mother and child because of the reduction in disease burden and saving the lives of young infants. Breastfeeding is associated with a myriad of positive benefits to the health of the child.
Other studies focused on the health implications of breastfeeding, with conflicting results. Rochat et al. (2016) conducted a study to establish the role of exclusive breastfeeding in promoting early child health. They focused on long-term child development benefits, as well as cognitive and emotional-behavioral development. Their study failed to demonstrate a relationship between exclusive breastfeeding and overall cognitive development. However, exclusive breastfeeding was associated with fewer behavioral related disorders. Although the evidence is weak, the study revealed a mediating effect of the breastfeeding practice in preventing detrimental health effects. Therefore, breastfeeding together with other maternal factors, such as the level of education might lead to improvement in cognitive functioning and prevent behavioral challenges.
Gaps in Research
Although some studies have revealed a connection between exclusivity and breastfeeding duration on child development (Deoni et al., 2013; von Stumm & Plomin, 2015), others, especially systematic reviews, have shown conflicting and contradictory results (Walfisch, Sermer, Cressman, & Koren, 2013). In another systematic review of six previous studies, Delgado and Matijasevich (2013) found contradicting results regarding the effect of breastfeeding on child development. The research suggested that evidence regarding the influence of the duration of breastfeeding on child development is limited. Besides, most of the reviewed studies fail to account for other possible factors, mother and child, that might affect growth in various aspects, including motor and cognitive. Therefore, additional research is critical to establish the actual effect of breastfeeding on the motor and cognitive development.
The literature review covers essential knowledge about the effect of breastfeeding on child development. The study used 25 sources with relevant information on the topic of study. Although all the sources offered relevant information, they provided conflicting evidence of the effect of breastfeeding and development, including motor and cognitive. The findings indicate that a need for additional research to establish the actual influence of breastfeeding on the two areas of child development, both short- and long-term, is required.