Case Based Pediatrics For Medical Students and Residents
Department of Pediatrics, University of Hawaii John A. Burns School of Medicine
Chapter II.2. Breastfeeding
Meta T. Lee, MD, MSEd
May 2002

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You are seeing a 7 day old infant for a routine post-nursery follow-up visit. The 18 year old first time mother is concerned that the baby is not eating enough. The infant is a normal full term male with no significant perinatal history. The baby drinks Enfamil 1-2 oz every 2-3 hours in addition to breastfeeding. She offers the baby the breast before each feed, but he either refuses to latch on or falls asleep after 5 minutes. When offered the bottle, he drinks about 1-2 ounces at a time. The mother complains that her breasts are full and tender, and that it hurts when the baby breastfeeds.

On review of systems, the baby is voiding 6-8 times a day, and stooling 4-6 times a day. There is no emesis, diarrhea, or excessive fussiness. FH is positive for allergies. The mother denies medical problems, denies prior surgeries, and is on no medications. SH is positive for a teen mother who lives with her parents. The father is not involved.

On exam, the infant is healthy appearing and has already surpassed his birth weight of 3700 grams. The exam is normal except for some mild jaundice to the face. The mother's breasts are hard, engorged, non-erythematous, and tender. Her nipples are cracked and bleeding.

You commend this mother on choosing breast milk as the preferred source of food for her infant. You reassure her that during the first six months of life, no additional liquids, foods, or vitamins are necessary for breastfed babies. You observe the baby and mother during a breastfeeding session in your office and explain that the pain experienced during breastfeeding is due to improper latch on. Improper latch on has also caused her nipples to crack and bleed, and resulted in inadequate excretion of milk. You explain to her that in order to maintain a good milk supply, milk needs to be removed from the breasts at least 8 to 12 times in every 24-hour period. You or your nurse teach her proper positioning and technique for proper latch on and refer her to the hospital lactation consultant for a next day appointment. You see her back in your office in 2-3 days and she reports that the baby is nursing much better and that her nipples and breasts are no longer painful.


Human milk is recommended as the optimal form of nutrition for infants (1). Breast milk contains the essential nutrition, immunomodulators, and anti-microbial agents for optimal growth and development. The AAP recommends exclusive breastfeeding to all infants in the first four to six months of life, and continued breastfeeding to at least the first year of life. However, national surveys report that 60% of women breastfeed postpartum, 30% exclusively breastfeed to six months of age, and an estimated 5% are still breastfeeding at 1 year of age (2). Although breastfeeding is the optimal nutritional source for growing infants, breastfeeding practices in this country are sub-optimal. Physicians can be influential in promoting and educating mothers about breastfeeding. This chapter presents a broad overview of basic concepts essential to understanding and promoting successful breastfeeding.

The breasts are paired mammary glands in which milk can be produced based on hormonal, psychological, and environmental influences. The smallest functioning unit of mature glandular tissue is the alveolus. Alveoli are composed of secretory acinar units, which are surrounded by myoepithelial cells. Myoepithelial cells form the contractile unit responsible for ejecting milk into ductal system. The ductal system is a branched pathway in which small ductules merge into larger ducts, which widen and drain into lactiferous sinuses. These collecting sinuses are located behind the nipple and the areola of the breast. Milk is transferred out of the lactiferous sinuses through multiple small openings on the nipple surface.

Lactogenesis begins during pregnancy. During pregnancy, breast size increases, as epithelial cells of the alveoli differentiate into secretory cells for milk production. Progesterone is responsible for the proliferation of glandular tissue and ductile development in breast tissue. Estrogen, placental lactogen, human chorionic gonadotropin, and human chorionic somatomammotropin also contribute to mammary gland growth during pregnancy. Prolactin is the primary hormone responsible for stimulating alveolar cells to produce milk. During pregnancy, high levels of progesterone inhibit prolactin from milk synthesis.

Hormonal changes occurring immediately after birth initiate the process of copious milk production. Following the delivery of the placenta, systemic levels of progesterone and estrogen drop steadily, while prolactin levels remain high. In addition, oxytocin, a hormone produced in the posterior pituitary, enables the milk-ejection or milk let-down reflex to occur. Tactile stimulus from the nursing infant releases oxytocin, which acts upon mammary myoepithelial cells to contract and force milk from the alveoli into the ducts toward the lactiferous sinuses where it becomes readily available for consumption.

The maintenance of milk production in lactation is dependent on systemic hormone regulation as well as autocrine regulation of the mammary gland. A peptide inhibitor in the mammary gland slows milk production unless it is removed by frequent nursing. Hence, lack of adequate milk removal results in stasis, and limited breast milk synthesis. Conversely, when frequent feeding occurs, the inhibitor is removed and milk production is increased. Hence, removal of milk from the breast facilitates continued milk production. This "supply-demand phenomenon" results in a feedback control mechanism that regulates the production of milk to match the intake of the infant.

Human milk contains protein, non-protein nitrogen compounds, lipids, oligosacccharides, vitamins, minerals, hormones, enzymes, growth factors and other protective agents. The composition of human milk is considered the "gold standard" to which all formulas attempt to recreate.

The major carbohydrate constituent of human milk is lactose. Small quantities of oligosaccharides, galactose and fructose are also present. Lactose concentration in human milk is relatively constant at 7gm/dl. This value varies with maternal diet. Lactose enhances calcium absorption and metabolizes readily to galactose and glucose, which supply energy to rapidly growing organs such as the brain.

Casein and whey are the major protein constituents. Human milk is composed of approximately 30% casein protein and 70% whey protein. Whey protein consists of five major components: alpha-lactalbumin, serum albumin, lactoferrin, immunoglobulins, and lysozyme. The latter three elements contribute to immunological defense. Oligosaccharides, nucleotides, growth factors, and cellular components of human milk also enhance the infant's immune system. Immunoglobulin A is also excreted into breast milk, which provides specific passive immunity against foreign antigens to which the mother is exposed.

The fat content in human milk is variable, and fluctuates with gestational age, maternal diet, and lactation patterns. Fat accounts for about one-half of the caloric value of human milk. Triglycerides are the main fat constituent, and are broken down into free fatty acids and glycerol by the enzyme lipase. The lipid portion of human milk contains essential fatty acids, which are important for brain growth and development.

The vitamin and mineral contents in human milk vary with maternal diet and genetic influences. Fat soluble vitamins A, E, D and K are present in human milk. Human milk is a good source of Vitamin A, which is required for vision and the maintenance of epithelial structures. Colostrum is rich in Vitamin E, an antioxidant that protects cell membranes in the retina and lungs against oxidant-induced injury. Vitamin D is present in low quantities in breast milk. Daily supplementation with Vitamin D is recommended to exclusively breastfed infants at risk for rickets. Infants at risk include children who are not adequately exposed to the sun and whose mothers who do not consume adequate nutrients. Vitamin K, required for the synthesis of blood clotting factors, is present in small amounts. Vitamin K supplementation in a single intramuscular injection at birth is recommended for all newborn infants even though it is normally produced in sufficient quantities by intestinal flora within a few days of birth.

Water soluble vitamins in human milk are very dependent upon maternal diet. Ascorbic acid, nicotinic acid, thiamine, B12, riboflavin, and pyridoxine (B6) levels increase with maternal ingestion of food containing these nutrients. Vitamin B12 is essential for early central nervous system development. Vitamin B12 supplementation should be considered for exclusive breastfed infants of strict vegetarian mothers.

The mineral content in breast milk is relatively constant. Sodium, iron, zinc, calcium, and other trace elements are present in human milk. Iron and calcium are present in small quantities in human milk, yet infants are able to absorb a greater proportion of these minerals than in cow's milk.

Advantages of breastfeeding

Human milk, through breastfeeding, provides nutritional, immunological, and developmental, benefits to infants. Studies have shown that human milk feeding decreases the incidence and severity of diarrhea, lower respiratory infections, otitis media, bacteremia, bacterial meningitis, botulism, urinary tract infections, and necrotizing enterocolitis (1). Limited studies also suggest a protective effect of human milk feeding against sudden infant death syndrome, insulin-dependent diabetes mellitus, Crohn's disease, ulcerative colitis, lymphoma, allergic diseases, and other chronic digestive diseases (1). There is also limited data that supports the potential for improved developmental outcome in certain breastfed infants at risk for developmental delay (3).

Mothers also benefit from breastfeeding. Increased levels of oxytocin result in more rapid uterine involution and less postpartum bleeding. Some recent studies also support that lactating women have an earlier return to pre-pregnancy weight, delayed resumption of ovulation with increased child spacing, improved bone remineralization postpartum, reduction of hip fractures in the postmenopausal period, reduced risk of ovarian cancer, and reduced risk of premenopausal breast cancer (1).

Breastfeeding also results in social, economical, and psychological benefits. Breast milk requires no preparation, hence increases time available to spend with the newborn. Lower incidences of infections in breastfed infants result in fewer days of work missed by parents. Families who breastfeed are relieved from a substantial financial burden incurred from the purchase of infant formulas throughout the first year of life. Last but not least, increased maternal-infant bonding is one of the major advantages of breastfeeding.

Clinical Approach

Preparation for breastfeeding should begin during pregnancy. An ideal time to discuss breastfeeding with the family is at the prenatal visit. A complete breastfeeding history includes a thorough discussion of the parents' intended method of feeding and the mother's previous breastfeeding history. A review of systems should include the incidence of previous postpartum hemorrhage and anomalies of the breast or nipple. Past medical history should include history of chronic medical illnesses, including seizure disorders, thyroid disorders, psychiatric disorders, or any other disorders requiring medications that may be contraindicated in breastfeeding. Past surgical history should include previous breast surgery, cardiac surgery, chest wall surgery, or breast trauma. A thorough medication history should be obtained. Family history should include incidence of breast cancer. Social history should include an assessment of the social support structure, as well as past or current history of illicit drug use and tobacco. Finally, questions the mother may have regarding breast changes during pregnancy or breastfeeding should be answered.

Breastfeeding is recommended as soon as possible after birth, preferably within the first hour of life. Immediate and sustained contact between mother and infant strongly correlates with longer durations of breastfeeding (4). During the first 48 hours of life, it is strongly recommended that a pediatrician, nurse, or lactation consultant observe and assist with at least one feeding in the hospital to document good breastfeeding technique prior to discharge. A follow-up visit is strongly recommended 48 to 72 hours after nursery discharge to ensure sustained adequate breastfeeding.

Anticipatory guidance should be directed at maintaining good breastfeeding technique, understanding signs of adequate intake, and forewarning new parents of the demanding and relentless feeding patterns of newborn infants.

Good breastfeeding technique requires proper positioning of the infant's body with proper "latch on", or attachment at the breast. An infant is in optimal positioning when the head and face are squarely in front of the breast, with the body in proper alignment with the head. Several positions of body alignment have been well described. In the "Madonna" position the infant lies across the mother's chest, with the infant's abdomen squarely facing the mother's chest. In the "football" position, the infant is "clutched" across the mother's side with the feet and body encompassing the side of the mother's body. In either position, the infant's head and body must be in proper alignment such that the infant is lying comfortably, with the mother's hand or arm firmly supporting the head.

An infant demonstrates good latch on when after properly positioned against the mother's body and triggered with an active rooting reflex, there is a wide opening of the jaw with relaxed lips that encompass contact beyond the nipple into the areolar space. Ensuring good latch on can prevent most common breastfeeding problems, such as sore nipples, engorgement, low milk supply, hyperbilirubinemia, and an unsatisfied baby.

Signs of good breastfeeding include the following: audible rhythmic swallowing during nursing, breasts feeling less full after each feeding session, at least 1-2 wet diapers per day for the first 2 days of life, 4-6 wet diapers every 24 hours after the 3rd day of life, and at least 3-4 bowel movements every 24 hours. Lack of persistent pain during breastfeeding sessions and absence of sore nipples are also signs of appropriate breastfeeding.

Anticipatory guidance on expected frequent feedings and nighttime awakenings can be helpful to new parents. Breastfed infants will often awake every few hours from hunger, and need to be fed at night to maintain growth. In addition, breastfeeding needs to occur at night in order to maintain adequate milk production. Hence, mothers should be prepared to expect to breastfeed newborns at least 8 to 12 times in a 24-hour period. Parents should also understand that newborns feed better when following their own sleep/wake cycles rather than when awakened around the clock. However, parents must understand that newborns in the first few weeks of life should be awakened if more than 4 hours pass between feedings.

Contraindications and Precautions

There are special conditions in which breastfeeding should not be recommended. Infants with galactosemia lack the essential enzymatic function to adequately digest the lactose component of human milk. Mothers with untreated active tuberculosis, human immunodeficiency virus, human T-lymphocytic virus, or active herpes simplex virus on the breast can impose infectious health risks to breastfeeding infants. Breastfeeding should not be recommended in these instances.

Drugs given to mothers by various routes can also potentially affect a breastfed infant. The amount of drug that passes from the maternal bloodstream into human milk is variable and dependent on molecular size, pH of milk, pKa of the drug, fat solubility, and transport mechanisms. The amount of drug that reaches the infant's bloodstream is usually a very small percentage of the mother's dosage. Absolute drug related contraindications to breastfeeding include radioactive isotypes, antimetabolites, and cancer chemotherapy agents. There are a small number of other drugs, which have been shown to have potentially harmful effects on breastfeeding infants. All maternal drugs should be evaluated for breastfeeding safety through reference textbooks or local resources.

Previous breast or chest wall surgery is not a contraindication to breastfeeding (4). However, women who have had previous breast or chest wall surgery or trauma may have impaired lactation performance due to significant cutting of ducts or nerves important in the lactation process. Breastfeeding care should be individualized, and infants should be followed frequently for appropriate weight gain.

The American Academy of Pediatrics recommends that pediatricians promote and support breastfeeding enthusiastically. At the individual level, pediatricians are encouraged to take a strong position in favor of breastfeeding, as well as become knowledgeable and skilled in the physiology and clinical management of breastfeeding. At the local level, pediatricians are encouraged to work collaboratively with the obstetric and nursing community, promote hospital policies and procedures to facilitate breastfeeding, and become familiar with local breastfeeding resources. At the community and national level, pediatricians can also work to reform insurance coverage of necessary breastfeeding services and supplies, promote breastfeeding education as a routine component of medical school and residency education, and encourage the media to portray breastfeeding as positive and the norm.


Questions

1. What is the prevalence of breastfeeding in the United States?

2. What are the Healthy People 2010 goals for breastfeeding?

3. What is the American Academy of Pediatrics' position on breastfeeding?

4. What are the advantages and disadvantages of breastfeeding?

5. What anatomic and physiologic changes occur in the process of lactogenesis?

6. What is the difference between human milk and infant formula?

7. What are the barriers that prevent women from successfully breastfeeding?

8. What are some clinical indications that suggest inadequate or sub optimal breastfeeding?

9. What can health care providers do to improve breastfeeding practices for their patients?


References

1. American Academy of Pediatrics: Workgroup on Breastfeeding. Breastfeeding and the Use of Human Milk (RE9729). Pediatrics 1997;100(6):1035-1039.

2. Hill PD. Update on Breastfeeding: Healthy People 2010 Objectives. Am J Mat Child Nurs 2000;25(5):248-251.

3. Reynolds A. Breastfeeding and Brain Development. Pediatr Clin North Am 2001;48(1):159-171.

4. Powers NG. Breastfeeding Update 2: Clinical Lactation Management. Pediatr Rev 1997;18(5):147-161.

5. Hall RT. Infant Feeding. Pediatr Rev 2000;21(6):191-199.

6. Slusser W. Breastfeeding Update 1: immunology, nutrition, and advocacy. Pediatr Rev 1997;18(8):265.

7. Riordan J, Auerbach KG, eds. Breastfeeding and Human Lactation, second edition. 1999, Boston: Jones and Bartlett Publishers, Inc.

8. Biancuzzo M. Breastfeeding the Newborn: Clinical Strategies for Nurses. 1999, St. Louis: Mosby, Inc.


Answers to questions

1. Approximately 60% of women breastfeed immediately post-partum, 20% are still breastfeeding at 6 months, and less than 5% are still breastfeeding at 1 year.

2. The Healthy People initiative set a target to increase the proportion of mothers who exclusively breastfeed to 75% at post-partum, 50% at 6 months, and 25% at 1 year.

3. The AAP recommends exclusive breastfeeding for the first 4-6 months of life, with continued breastfeeding to at least 12 months of age, and thereafter for as long as mutually desired.

4. Advantages of breastfeeding include health, nutritional, immunologic, developmental, psychological, social, economic, and environmental benefits. The major disadvantages to breastfeeding include time and energy required of the mother, decreased paternal (father) participation, and lack of universal social acceptance of breastfeeding practices by the public.

5. Anatomic and physiologic changes that occur in the breast include: a) differentiation of epithelial alveolar cells into secretory cells for milk production. b) proliferation of glandular tissue and ductile development by progesterone. c) copious milk production following placental expulsion due to prolactin unopposed by progesterone. d) milk ejection or milk let-down reflex by oxytocin.

6. Carbohydrate, protein, and fat composition differ. Human milk contains lactose as the main carbohydrate source, high whey to casein protein ratio, and variable fat stores which are dependent on maternal diet. Formulas have variable carbohydrate source which include lactose, starch or other complex carbohydrates. Protein sources can also vary by formula type: casein, whey, soy or protein hydrolysate. Fat sources in infant formula can vary as well: triglycerides with long or medium chains, etc. Breastmilk has more absorbable iron, calcium and zinc than formula.

7. Barriers to successful breastfeeding include: physician misinformation and apathy, insufficient prenatal breastfeeding education, inappropriate interruption of breastfeeding, early hospital discharge, and late hospital follow-up care.

8. Indicators for inadequate breastfeeding include: less than 6 urinations per day and 3-4 stools per day by day 5-7 of life, decreased activity level, difficulty arousing, weight loss of greater than 15% of birth weight within the first week of life.

9. Provide good breastfeeding education at the prenatal visit, be well educated on anatomy and physiology of breastfeeding, advocate for breastfeeding policies.


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