Breastfeeding Rates

Breastfeeding rates in the United States have risen steadily over the past decade. The Centers for Disease Control and Prevention (CDC, 2012) reported that the U.S. breastfeeding initiation rate in 2009 was 76.9%, which is the highest ever reported. The 6-month breastfeeding rate was 47.2%, and the 12-month rate was 25.5%. The rate of exclusive breastfeeding at 3 months was 36% and at 6 months, 16.3%. In spite of the increases in breastfeeding rates, the United States continues to fall short of the Healthy People 2020 goals of 81% of infants ever breastfed, 60.6% breastfeeding at 6 months, and 34.1% at 12 months; goals for exclusive breastfeeding are 46.2% through 3 months and 25.5% through 6 months (USDHHS, 2010).

Trends remain unchanged in breastfeeding rates among minority groups in the United States. The lowest breastfeeding rates are among non-Hispanic black women (Jensen, 2012), although the overall percentage of non-Hispanic black women who breastfeed has increased in recent years. The minority group most likely to breastfeed is Hispanic women (Scanlon, Grummer-Strawn, Li et al., 2010).

Benefits of Breastfeeding

Extensive evidence exists concerning the health benefits of breastfeeding and human milk for infants, with some of the benefits extending into adulthood (Table 24-1). These benefits are optimized when infants are breastfed exclusively and when the duration of breastfeeding is increased (Mass, 2011). The evidence supporting breastfeeding as the ideal form of infant nutrition is so strong that health care professionals may need to present information about it from two perspectives: benefits of and risks of not breastfeeding (Spatz and Lessen, 2011).

Breastfeeding is associated with health benefits for mothers (see Table 24-1). The benefits are increased with the number of children who were breastfed and the total length of time of lactation.

The psychologic benefits for mothers include enhanced bonding and attachment. For many women breastfeeding is associated with a sense of empowerment in the ability to provide nutrition for the infant.

Breastfeeding is convenient. The milk is ready to feed and at the proper temperature. In most cases there is no need for bottles or other equipment.

The economic benefits of breastfeeding affect families, employers, insurers, and the entire nation. Because infant formula is expensive, breastfeeding represents a significant savings for families. It reduces health care costs and decreases employee absenteeism. It has been estimated that the United States could save $13 billion dollars per year and more than 900 infant deaths could be prevented if 90% of infants were breastfed exclusively for 6 months (Bartick and Reinhold, 2010).

Breastfeeding has environmental benefits. It reduces the waste that is deposited in landfills, including formula packaging, bottles, nipples, and other equipment. There is no need for fuel to prepare or transport human milk, which saves energy resources (USDHHS, 2011).

Choosing to Breastfeed

Women most often choose to breastfeed because they are aware of the benefits to the infant (Nelson, 2012). This reinforces the importance of prenatal education about the numerous benefits of breastfeeding.

Breastfeeding is a natural extension of pregnancy and childbirth; it is much more than simply a means of supplying nutrition for infants. Many women seek the unique bonding experience between mother and infant that is characteristic of breastfeeding.

Women tend to select the same method of infant feeding for each of their children. If the first child was breastfed, subsequent children will likely also be breastfed.

The support of the partner and family is a major factor in the mother’s decision to breastfeed. Women who perceive their partners to prefer breastfeeding are more likely to breastfeed. Women are more likely to breastfeed successfully when partners and family members are positive about breastfeeding and have the skills to support it.

Cultural factors influence infant feeding decisions. For example, in the Hispanic culture breastfeeding is the norm, whereas formula feeding is more common among African-American families (see Cultural Competence box).

The decision to breastfeed exclusively is related to the mother’s knowledge about the health benefits to the infant and her comfort level with breastfeeding in social settings (Stuebe and Bonuck, 2011). The likelihood that women will breastfeed exclusively may be greater if they made the decision to do so during pregnancy (Tenfelde, Finnegan, and Hill, 2011).

There appears to be a relationship between maternal weight and infant feeding decisions. Women who are overweight or obese are less likely to breastfeed than women who are underweight or of average weight (Mehta, Siega-Riz, Herring, et al., 2011).

Other factors influence decisions about infant nutrition. Social and systemic factors create obstacles or barriers to breastfeeding among women in the United States. These include a lack of broad social support for breastfeeding and the widespread marketing by infant formula companies. In addition, there is a lack of prenatal breastfeeding education for expectant parents and insufficient training/education of health care professionals about breastfeeding. In some institutions the policies and practices do not support exclusive breastfeeding (Mass, 2011). There is a lack of support for breastfeeding mothers during the first 2 to 3 weeks after birth when they are most likely to encounter difficulties.

On a more personal level, a major obstacle for women is employment and the need to return to work after birth (Mass, 2011). A lack of support from the partner and family also creates obstacles to breastfeeding for many women. In a meta-synthesis of 14 qualitative studies about infant feeding decision making, Nelson (2012) reported common barriers to breastfeeding such as lack of comfort or uneasiness with breastfeeding, pain, lifestyle incompatibility, discomfort with public breastfeeding, and a lack of formal support.

Choosing to Formula Feed

Parents who choose to formula feed often make this decision without complete information and understanding of the benefits of breastfeeding. Even women who are educated about the advantages of breastfeeding may still decide to formula feed. Cultural beliefs and myths and misconceptions about breastfeeding influence women’s decision making. Many women see bottle-feeding as more convenient or less embarrassing than breastfeeding. Some view formula feeding as a way to ensure that the father, other family members, and day care providers can feed the baby. Some women lack confidence in their ability to produce breast milk of adequate quantity or quality. Women who have had previous unsuccessful breastfeeding experiences may choose to formula feed subsequent infants. Some women see breastfeeding as incompatible with an active social life, or they think that it will prevent them from going back to work. Modesty issues and societal barriers exist against breastfeeding in public. A major barrier for many women is the influence of family and friends (Nelson, 2012).

Women who participate in the Supplemental Nutrition Program for Women, Infants, and Children (WIC) are more likely to formula feed (Jensen, 2012; Mass, 2011). Although in recent years WIC has improved food packages for breastfeeding families, many women on WIC decide to formula feed based on the perceived monetary value of infant formula as well as convenience and social factors (Jensen, 2012).

Contraindications to Breastfeeding

Breastfeeding is contraindicated in a few circumstances. Newborns who have galactosemia should not receive human milk. Breastfeeding is contraindicated for mothers who are positive for human T-cell lymphotropic virus types I or II and those with untreated brucellosis. Women should not breastfeed if they have active tuberculosis (TB) or if they have active herpes simplex lesions on the breasts. However, neither of these conditions precludes a mother expressing milk for her infant (AAP Section on Breastfeeding, 2012). Women with active TB can breastfeed when they have been treated for at least 2 weeks and are deemed noninfectious. Varicella that occurs 5 days before or 2 days after birth and acute H1N1 infection require temporary separation of mother and infant. In both instances it is safe for infants to receive expressed milk (AAP Section on Breastfeeding, 2012).

In the United States maternal human immunodeficiency virus (HIV) infection is considered a contraindication for breastfeeding (AAP Section on Breastfeeding, 2012). However, that is not true in other countries. In developing countries where HIV is prevalent, the benefits of breastfeeding for infants outweigh the risk of contracting HIV from infected mothers (WHO, UNICEF, UNFPA, and UNAIDS, 2010).

Breastfeeding is not recommended when mothers are receiving chemotherapy or radioactive isotopes (e.g., with diagnostic procedures). Maternal use of mood-altering drugs (“street drugs”) is incompatible with breastfeeding (AAP Section on Breastfeeding, 2012). Other maternal medications may also be incompatible with and require temporary or permanent cessation of breastfeeding.

Cultural Influences on Infant Feeding

Cultural beliefs and practices are significant influences on infant feeding methods. Although recognized cultural norms exist, one cannot assume that generalized observations about any cultural group hold true for all members of that group. Many regional and ethnic cultures are found within the United States. Dealing effectively with these groups requires that nurses be knowledgeable and sensitive to the cultural factors influencing infant feeding practices.

In general people who have immigrated to the United States from poorer countries often choose to formula feed their infants because they believe it is a better, more “modern” method or because they want to adapt to U.S. culture and perceive that formula feeding is the custom. Hispanic women who are more acculturated may be less likely to breastfeed and, if they do, tend to breastfeed for a shorter duration (Ahluwalia, D’Angelo, Morrow, et al., 2012).

Breastfeeding beliefs and practices vary across cultures. For example, among the Muslim culture breastfeeding for 24 months is customary. Before the first feeding rubbing a small piece of softened date on the newborn’s palate is a ritual. Because of the cultural emphasis on privacy and modesty, Muslim women may choose to bottle-feed formula or expressed breast milk while in the hospital. Because of beliefs about the harmful nature or inadequacy of colostrum, some cultures apply restrictions on breastfeeding for a period of days after birth. Such is the case for many cultures in Southern Asia, the Pacific Islands, and parts of sub-Saharan Africa. Before the mother’s milk is deemed to be “in,” babies are fed prelacteal food such as honey or clarified butter in the belief that these substances will help clear out meconium. Other cultures begin breastfeeding immediately and offer the breast each time the infant cries.

A common practice among Mexican women is las dos cosas (“both things”). This refers to combining breastfeeding and commercial infant formula. It is based on the belief that, by combining the two methods, the mother and infant receive the benefits of breastfeeding, and the infant receives the additional vitamins from infant formula (Bartick and Reyes, 2012; Rios, 2009). This practice can result in problems with milk supply and babies refusing to latch on to the breast, which can lead to early termination of breastfeeding.

Some cultures have specific beliefs and practices related to the mother’s intake of foods that foster milk production. Korean mothers often eat seaweed soup and rice to enhance milk production. Hmong women believe that boiled chicken, rice, and hot water are the only appropriate nourishments during the first postpartum month. The balance between energy forces, hot and cold, or yin and yang is integral to the diet of the lactating mother. Hispanics, Vietnamese, Chinese, East Indians, and Arabs often use this belief in choosing foods. “Hot” foods are considered best for new mothers. This belief does not necessarily relate to the temperature or spiciness of foods. For example, chicken and broccoli are considered “hot,” whereas many fresh fruits and vegetables are considered “cold.” Families often bring desired foods into the health care setting.

Energy

Infants require adequate caloric intake to provide energy for growth, digestion, physical activity, and maintenance of organ metabolic function. Energy needs vary according to age, maturity level, thermal environment, growth rate, health status, and activity level. For the first 3 months the infant needs 110 kcal/kg/day. From 3 months to 6 months the requirement is 100 kcal/kg/day. This level decreases slightly to 95 kcal/kg/day from 6 to 9 months and increases to 100 kcal/kg/day from 9 months to 1 year (AAP Committee on Nutrition, 2009).

Human milk provides an average of 67 kcal/100 mL or 20 kcal/oz. The fat portion of the milk provides the greatest amount of energy. Infant formulas simulate the caloric content of human milk. Usually a standard formula contains 20 kcal/oz, although the composition differs among brands.

Carbohydrates

According to the Institute of Medicine (IOM, 2005), the recommended adequate intake (AI) for carbohydrates in the first 6 months of life is 60 g/day and 95 g/day for the second 6 months. Because newborns have only small hepatic glycogen stores, carbohydrates should provide at least 40% to 50% of the total calories in the diet. Moreover newborns may have a limited ability to carry out gluconeogenesis (the formation of glucose from amino acids and other substrates) and ketogenesis (the formation of ketone bodies from fat), the mechanisms that provide alternative sources of energy.

As the primary carbohydrate in human milk and commercially prepared infant formula, lactose is the most abundant carbohydrate in the diet of infants up to age 6 months. Lactose provides calories in an easily available form. Its slow breakdown and absorption also increase calcium absorption. Corn syrup solids or glucose polymers are added to infant formulas to supplement the lactose in the cow’s milk and thereby provide sufficient carbohydrates.

Oligosaccharides, another form of carbohydrate found in breast milk, are critical in the development of microflora in the intestinal tract of the newborn. These prebiotics promote an acidic environment in the intestines, preventing the growth of gram-negative and other pathogenic bacteria, thus increasing the infant’s resistance to gastrointestinal (GI) illness.

Fat

Fats provide a major energy source for infants, supplying as much as 50% of the calories in breast milk and formula. The recommended AI of fat for infants younger than 6 months is 31 g/day (IOM, 2005). The fat content of human milk is composed of lipids, triglycerides, and cholesterol; cholesterol is an essential element for brain growth. Human milk contains the essential fatty acids (EFAs) linoleic acid and linolenic acid and the long-chain polyunsaturated fatty acids arachidonic acid (ARA) and docosahexaenoic acid (DHA). Fatty acids are important for growth, neurologic development, and visual function. Cow’s milk contains fewer of the EFAs and no polyunsaturated fatty acids. Most formula companies add DHA to their products, although there is a lack of evidence supporting the benefit (Lawrence and Lawrence, 2011b). Modified cow’s milk is used in most infant formulas; but the milk fat is removed, and another fat source such as corn oil, which the infant can digest and absorb, is added in its place. If whole milk or evaporated milk without added carbohydrate is fed to infants, the resulting fecal loss of fat (and therefore loss of energy) can be excessive because the milk moves through the infant’s intestines too quickly for adequate absorption to take place. This can lead to poor weight gain.

Protein

High-quality protein from breast milk, infant formula, or other complementary foods is necessary for infant growth. The protein requirement per unit of body weight is greater in the newborn than at any other time of life. For infants younger than 6 months the recommended AI for protein is 9.1 g/day (IOM, 2005).

Human milk contains the two proteins whey and casein in a ratio of approximately 70 : 30 compared with the ratio of 20 : 80 in most cow’s milk–based formula (Blackburn, 2013). This whey/casein ratio in human milk makes it more easily digestible and produces the soft stools seen in breastfed infants. The primary whey protein in human milk is α-lactalbumin; this protein is high in essential amino acids needed for growth. The whey protein lactoferrin in human milk has iron-binding capabilities and bacteriostatic properties, particularly against gram-positive and gram-negative aerobes, anaerobes, and yeasts. The casein in human milk enhances the absorption of iron, thus preventing iron-dependent bacteria from proliferating in the GI tract (Lawrence and Lawrence, 2011a). The amino acid components of human milk are uniquely suited to the newborn’s metabolic capabilities. For example, cystine and taurine levels are high, whereas phenylalanine and methionine levels are low.

Vitamins

With the exception of vitamin D, human milk contains all of the vitamins required for infant nutrition, with individual variations based on maternal diet and genetic differences. Vitamins are added to cow’s-milk formulas to resemble levels found in breast milk. Although cow’s milk contains adequate amounts of vitamins A and B complex, vitamin C (ascorbic acid), vitamin E, and vitamin D must be added.

Vitamin D facilitates intestinal absorption of calcium and phosphorus, bone mineralization, and calcium resorption from bone. According to the AAP, all infants who are breastfed or partially breastfed should receive 400 International Units of vitamin D daily, beginning the first few days of life. Nonbreastfeeding infants and older children who consume less than 1 quart per day of vitamin D–fortified milk should also receive 400 International Units of vitamin D each day (Wagner, Grier, and AAP Section on Breastfeeding and Committee on Nutrition, 2008).

Vitamin K, required for blood coagulation, is produced by intestinal bacteria. However, the gut is sterile at birth, and a few days are required for intestinal flora to become established and produce vitamin K. To prevent hemorrhagic problems in the newborn an injection of vitamin K is given at birth to all newborns, regardless of feeding method (AAP Section on Breastfeeding, 2012).

The breastfed infant’s vitamin B₁₂ intake depends on the mother’s dietary intake and stores. Mothers who are on strict vegetarian (vegan) diets and those who consume few dairy products, eggs, or meat are at risk for vitamin B₁₂ deficiency. Breastfed infants of vegan mothers should be supplemented with vitamin B₁₂ from birth.

Minerals

The mineral content of commercial infant formula is designed to reflect that of breast milk. Unmodified cow’s milk is much higher in mineral content than human milk, which also makes it unsuitable for infants during the first year of life. Minerals are typically highest in human milk during the first few days after birth and decrease slightly throughout lactation.

The ratio of calcium to phosphorus in human milk is 2 : 1, an optimal proportion for bone mineralization. Although cow’s milk is high in calcium, the calcium/phosphorus ratio is low, resulting in decreased calcium absorption. Consequently young infants fed unmodified cow’s milk are at risk for hypocalcemia, seizures, and tetany. The calcium/phosphorus ratio in commercial infant formula is between that of human milk and cow’s milk.

Iron levels are low in all types of milk; however, iron from human milk is better absorbed than iron from cow’s milk, iron-fortified formula, or infant cereals. Breastfed infants draw on iron reserves deposited in utero and benefit from the high lactose and vitamin C levels in human milk that facilitate iron absorption. Full-term infants have enough iron stores from the mother to last for the first 4 months. After 4 months of age, infants who are exclusively breastfed are at risk for iron deficiency. The AAP recommends giving exclusively breastfed infants an iron supplement (1 mg/kg/day) beginning at 4 months and continuing until the infant is consuming iron-containing complementary foods such as iron-fortified cereals. Infants who are partially breastfed should receive the same iron supplement if more than half of their daily feedings consists of human milk and they are not consuming iron-rich foods (Baker, Greer, and the AAP Committee on Nutrition, 2010). Formula-feeding infants should receive an iron-fortified commercial infant formula until 12 months of age. Infants younger than 1 year should never be fed whole milk (Baker, Greer, and the AAP Committee on Nutrition, 2010).

Fluoride levels in human milk and commercial formulas are low. This mineral, which is important in preventing dental caries, can cause spotting of the permanent teeth (fluorosis) in excess amounts. Experts recommend that no fluoride supplements be given to infants younger than 6 months. From 6 months to 3 years, fluoride supplements are based on the concentration of fluoride in the water supply (AAP Section on Breastfeeding, 2012).

Lactogenesis

After the mother gives birth a precipitous fall in progesterone triggers the release of prolactin from the anterior pituitary gland. During pregnancy prolactin prepares the breasts to secrete milk and during lactation to synthesize and secrete milk. Prolactin levels are highest during the first 10 days after birth, gradually declining over time but remaining above baseline levels for the duration of lactation. Prolactin is produced in response to infant suckling and emptying of the breasts (Fig. 24-3, A). Milk production is a supply-meets-demand system (i.e., as milk is removed from the breast, more is produced). Incomplete removal of milk from the breasts can lead to decreased milk supply. Oxytocin is essential to lactation. As the nipple is stimulated by the suckling infant, the posterior pituitary is prompted by the hypothalamus to produce oxytocin. This hormone is responsible for the milk ejection reflex (MER), or let-down reflex (see Fig. 24-3, B). The myoepithelial cells surrounding the alveoli respond to oxytocin by contracting and sending the milk forward through the ducts to the nipple. The MER is triggered multiple times during a feeding session. Thoughts, sights, sounds, or odors that the mother associates with her baby (or other babies) such as hearing the baby cry can trigger the MER. Many women report a tingling “pins and needles” sensation in the breasts as milk ejection occurs, although some mothers can detect milk ejection only by observing the sucking and swallowing of the infant. The MER also can occur during sexual activity because oxytocin is released during orgasm. The reflex can be inhibited by fear, stress, and alcohol consumption.

Oxytocin is the same hormone that stimulates uterine contractions during labor. Consequently the MER can be triggered during labor, as evidenced by leakage of colostrum. This reflex readies the breasts for immediate feeding by the infant after birth. Oxytocin has the important function of contracting the mother’s uterus after birth to control postpartum bleeding and promote uterine involution. Thus mothers who breastfeed are at decreased risk for postpartum hemorrhage. Uterine contractions that occur with breastfeeding are often painful during and after feeding for the first 3 to 5 days. These “afterpains” are more common in multiparas and tend to resolve completely within 1 week after birth.

Prolactin and oxytocin have been called the mothering hormones because they affect the postpartum woman’s emotions and her physical state. Many women report feeling thirsty or very relaxed during breastfeeding, probably as a result of these hormones.

The nipple-erection reflex is an important part of lactation. When the infant cries, suckles, or rubs against the breast, the nipple becomes erect, which aids in the propulsion of milk through the ducts to the nipple pores. Nipple sizes, shapes, and ability to become erect vary with individuals. Some women have flat or inverted nipples that do not become erect with stimulation; these women likely need assistance with effective latch. Their infants should not be offered bottles or pacifiers until breastfeeding is well established.

Uniqueness of Human Milk

Human milk is the ideal food for human infants. It is a dynamic substance with a composition that changes to meet the changing nutritional and immunologic needs of the growing infant. Breast milk is specific to the needs of each infant; for example, the milk produced by mothers of preterm infants differs in composition from that of mothers who give birth at term.

Human milk contains immunologically active components that provide some protection against a broad spectrum of bacterial, viral, and protozoal infections. The major immunoglobulin (Ig) in human milk is secretory IgA; IgG, IgM, IgD, and IgE are also present. Human milk also contains T and B lymphocytes, epidermal growth factor, cytokines, interleukins, bifidus factor, complement (C3 and C4), and lactoferrin, all of which have a specific role in preventing localized and systemic bacterial and viral infections (Lawrence and Lawrence, 2011a).

Human milk composition and volumes vary according to the stage of lactation. In lactogenesis stage I, beginning at approximately 16 to 18 weeks of pregnancy, the breasts are preparing for milk production by producing prepartum milk or colostrum. Stage II of lactogenesis begins with birth as progesterone levels drop sharply when the placenta is removed. For the first 2 to 3 days after birth, the baby receives colostrum, a clear, yellowish fluid that is rich in antibodies and higher in protein but lower in fat than mature milk. The high protein level of colostrum facilitates binding of bilirubin, and the laxative action of colostrum promotes early passage of meconium. Colostrum is important in the establishment of normal Lactobacillus bifidus flora in the infant’s digestive tract. It gradually changes to transitional milk. By 3 to 5 days after birth the woman experiences a noticeable increase in milk production. This is often referred to as the milk coming in. Breast milk continues to change in composition for approximately 10 days, when the mature milk is established. This is stage III of lactogenesis (Lawrence and Lawrence, 2011a).

The composition of human milk changes over time as the infant grows and develops. Fat is the most variable component of human milk with changes in concentration over a feeding, over a 24-hour period, and across time. Variations in fat content exist between breasts and among individuals (Lawrence and Lawrence, 2011a). During each feeding the concentration of fat gradually increases from the lower fat foremilk to the richer hindmilk. The hindmilk contains the denser calories from fat necessary for ensuring optimal growth and contentment between feedings. Because of this changing composition of human milk during each feeding, breastfeeding the infant long enough to supply a balanced feeding is important.

Milk production gradually increases as the baby grows. Infants have fairly predictable growth spurts (at approximately 10 days, 3 weeks, 6 weeks, 3 months, and 6 months), when more frequent feedings stimulate increased milk production. These growth spurts usually last 24 to 48 hours, after which the infants resume their usual feeding pattern as the mother’s milk supply increases.