How Long Should Mothers Breastfeed?

Imagine that the world had created a new "dream product" to feed and immunize everyone born on Earth. Imagine also that it was available everywhere, required no storage or delivery, and helped mothers plan their families and reduce the risk of cancer. Then imagine that the world refused to use it." —Frank Oski, M.D.

Many argue that mothers can't go wrong with breastfeeding. Not only do children who are breastfed as infants tend to have fewer health problems, greater cognitive functioning, and better communication skills than children who aren't breastfed, but their mothers benefit as well. Along with lower risks of ovarian and breast cancer, new mothers who breastfeed are also likely to have fewer problems with postpartum depression and fewer difficulties bonding with their children.

But what are the long-term benefits of breastfeeding? Most research studies looking at the emotional benefits involved focus on the first few years of a child's life, without looking at later development. There also seems to be some controversy over how long a child should be breastfed, and whether there are benefits to continuing with breastfeeding after the first few weeks of life. Though the World Health Organization recommends that children be breastfed exclusively for the first six months while being slowly weaned off after one to two years of age, there seems to be surprising resistance to these common sense directives.

Worldwide, only an estimated 38 percent of children are breastfed exclusively for the first six months, and in the United States alone, that statistic drops to 13 percent. In an era where more alternatives are available, including commercial formulas advertised as being just as nourishing as mother's milk, many women are encouraged to stop breastfeeding early, despite these recommended guidelines. As a result, researchers are taking a closer look at what this can mean for later development.

One particular factor being investigated is maternal sensitivity, or the responsiveness that mothers have to their babies, including their ability to read the various cues that babies give off to express their needs and desires, as well as whether they respond to those cues appropriately. As children grow older, this maternal sensitivity evolves as well and often shapes the relationship between mother and child throughout adolescence and beyond. While breastfeeding is encouraged as a way to build maternal sensitivity, actual research looking at how breastfeeding affects the emotional bond between mothers and their children has been lacking up to now.

But a new research article published in the journal Developmental Psychology may provide some answers. In the article, Jennifer M. Weaver of Boise State University and a team of researchers presented the results of a longitudinal study looking at mothers and their infants and following those children throughout their first decade of life. Using data taken from the Study of Early Child Care and Youth Development, conducted by the National Institute of Child Health and Human Development (NICHD), 1,272 adult participants and their children were evaluated for the purpose of this study.

All the mothers went through an initial interview when their infants were one month old. The participants then completed later assessments when the children were 3, 6, 12, 15, 24, 36, 42, 46, 50, and 54 months old, and later at ages 5, 6, 7, 9, 11, 14, and 15 years. This included collecting information on:

• Parental sensitivity: The sensitivity of mothers was measured using blind coding on eight videotaped interactions between parents and their children collected between infancy and age 11. The videotapes showed free play scenarios and problem-solving tasks that parents carried out with their children. The free play scenarios included asking mothers to play freely with their children for 15 minutes using a set of provided toys. Problem-solving tasks involved the use of a specially adapted Etch-a-sketch, which mothers and children operated together. Parents were rated on the emotional and instrumental support they showed their children, as well as how they interacted to solve a given task. Since quality of maternal sensitivity changed over time as children grew older, this was taken into account by the raters. Sensitivity ratings were also obtained for fathers on a subset of the total sample.
• Breastfeeding duration: During the interviews, mothers were asked about their breastfeeding practices, including how old their children were when breastfeeding ended. While three out of four mothers reported some breastfeeding, only 2 percent of the total sample reported breastfeeding up to the age of 24 months. The average length of time for breastfeeding was 17 weeks.
• Maternal attitudes/personality factors: Mothers completed questionnaires measuring their disciplinary practices (child-centered versus more traditional views of discipline), as well as how they scored on a test of neuroticism.
• Attachment security: When each child was 24 months of age, testers visited the family home to observe their behavior over a two-hour period. The children were rated on the level of security they showed with their mothers, including how they reacted to being separated and how open they were to being with strangers.
• Demographic data: Demographic data was collected for all families, including the mothers' level of education, whether they were in a two-parent household, etc.

As expected, the results showed that longer breastfeeding (up to age 3) predicted increases in maternal sensitivity up to age 11. This relationship held up even after other factors were taken into account, such as maternal neuroticism, parental attitudes towards discipline, level of maternal education, and the presence of a romantic partner in the home.

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Results also showed a positive link between the duration of breastfeeding and attachment security in toddlers. Conversely, the duration of breastfeeding was an inverse predictor of maternal neglect over the first 15 years of life. No evidence for a direct link between attachment security and later maternal sensitivity was found, however. These results also applied exclusively to mothers and breastfeeding practices and didn't appear to play a role in the later sensitivity of fathers.

Based on their research, Jennifer Weaver and her colleagues conclude that breastfeeding has positive consequences that can persist in children well beyond the first few years of life. While they stress that the duration of breastfeeding is just one of many factors that can influence the development of a positive bond between mothers and their children, it still continues to be important for both parties.

Despite these positive findings, there are limitations to this research, including a lack of information on whether mothers were exclusively breastfeeding their infants or using mixed feeding, as well as possible selection effects, since high-risk families weren't included in the study. It may also help to explore some of the physiological factors that can underlie the link between breastfeeding and sensitivity, including hormonal and biochemical changes.

While more research is needed, studies such as this one highlight the importance of breastfeeding and show that the decision to breastfeed, as well as the decision as to how long the breastfeeding should continue, can be far more important than many parents realize.