Developmental Readiness of Normal Full Term Infants to Progress from Exclusive Breastfeeding to the Introduction of Complementary Foods
Audrey J. Naylor, Ardythe L Morrow
Wellstart International and the LINKAGES Project/Academy for Educational Development, Washington, D.C. 2001.
Introduction and Background
This review of the developmental readiness of normal full term infants to progress from exclusive breastfeeding to the introduction of complementary foods has been undertaken as a result of the international debate regarding the best age to introduce complementary (semi-solid and solid) foods into the diet of the breastfed human infant. Since 1979 the World Health Organization has recommended that normal full term infants should be exclusively breastfed for „four to six months.” Over the two decades since this recommendation was established further evidence regarding the benefits of breastmilk and breastfeeding has accumulated. In addition, there have been increasing reports suggesting an association between discontinuing exclusive breastfeeding prior to six months of age and an increase in infant morbidity and mortality. Throughout the world many professionals as well as a number of governments have concluded that there is sufficient evidence to recommend continuing exclusive breastfeeding for „about six months” Even within WHO, UNICEF and other international agencies, some documents continue to recommend exclusive breastfeeding for „four to six months” while others now use „about six months”. There is an urgent need to review this matter and determine whether or not there is sufficient scientific evidence to change in the global recommendation. WHO responded to this need and arranged for a review of the recent studies that relate duration of exclusive breastfeeding („four to six months versus six months”) to infant morbidity and mortality as well as growth and maternal health.
Another relevant aspect of this global concern that needs further attention relates to the infant’s internal biologic processes that are proceeding along largely genetically predetermined developmental pathways. These begin at the moment of conception, continue throughout life. A number of these developmental processes are important to infant feeding. The human neonate is delivered from a protected intrauterine environment - sterile, warm, and protective - following nine months of development during which the nutritional, immunologic and endocrine needs were provided for by maternal systems. The newly born infant can no longer obtain fluids, nutrients, and immune protection through the umbilical cord. The ambient temperature is no longer held at maternal body temperature and the environment is no longer sterile. Though this transition is filled with life threatening hazards, there are many biologically active protective systems in place to increase the likelihood of infant survival, some within the infant and some provided by the mother. Obvious and increasingly well understood is the ability of the normal mother-infant dyad to continue the flow of nutrients, fluids, immune substances and other biologically essential and active substances through frequent breastfeeding beginning very shortly after birth. This mother-baby interdependency works remarkably well for a number of months while the infant proceeds with its internally driven biological processes of growth and development. While some of these processes are very visible (physical growth, neuromotor development) others of equal importance are progressing without clear signs. Renal, hepatic, neurologic systems are gradually maturing. The infants own GI tract and immune system are becoming more prepared to become independent of the maternal resources. Oral motor abilities are also steadily progressing in preparation for the time when breastmilk alone will no longer is able to fulfill all infant nutritional and fluid needs. New oral motor functions will be called into action to assure successful continuation of the intake of foods and fluids.
