CHAPTER 29

Breastfeeding

Karen C. Bodnar, MD, IBCLC, FABM, FAAP

Human milk is the natural food source for human newborns and infants. It provides optimal nutrition and is an immunologically active compound that allows for early regulation of an infant’s immune system and priming of the microbiome. All formulas are incomplete attempts at replication. Human milk is made of water, fat, lactose-containing carbohydrates, and protein, as well as vitamins, immunoglobulins, prebiotics, enzymes, hormones, and even phagocytes and lymphocytes. It is a dynamic fluid that changes in composition as newborns and infants grow. Early colostrum is high in lactose and protein, composed of casein and whey, and quite immunologically active. Through lactogenesis, it becomes mature milk with much greater quantity and higher fat content. It thus has a lower concentration of protein but continues to contain all the immunologically active components of colostrum.

Epidemiology

Historically, newborns and infants were totally dependent on breastfeeding by their mother or a wet nurse for their survival. When formula feeding was attempted in the 1800s, the mortality rate in exposed newborns and infants was as high as 85%. Thus, the advantages of breastfeeding were recognized and still promoted in the early 1900s. Following the advent of pasteurization, cow’s milk formula became much safer than before pasteurization. Formula development allowed more mothers to enter the workforce, and breastfeeding rates declined over the course of the 20th century. Formula feeding became the norm as companies successfully marketed formulas. In 1972, at the nadir of breastfeeding, only 22% of babies were ever breastfed. However, current scientific understanding of the many benefits of breastfeeding for baby and mother has been the impetus to again promote breastfeeding as the preferred food source for newborns and infants.

In the United States today, following the Centers for Disease Control and Prevention Healthy People initiative, which included a national agenda calling for an increased rate of breastfeeding, 83.2% of mothers are initiating breastfeeding. The rate of mothers sustaining breastfeeding to 1 year of age is only 35.9%, however. Rates are lower in low socioeconomic groups and among women with lower levels of education. Ethnic disparities also exist, with the black population having the lowest rates of breastfeeding in the United States.

In 1991, the World Health Organization and the United Nations Children’s Fund developed the Baby-Friendly Hospital Initiative, delineating 10 steps to undertake in the hospital to promote successful breastfeeding. This initiative is used worldwide to improve breastfeeding rates. The American Academy of Pediatrics published its policy statement, “Breastfeeding and the Use of Human Milk,” in 2005 and a revised version in 2012. This policy endorses breastfeeding and delineates the physician responsibility to promote and support it. In 2011, the US Department of Health and Human Services issued The Surgeon General’s Call to Action to Support Breastfeeding. A national imperative now exists to promote breastfeeding.

Anatomy and Physiology of Lactation

The breasts consist of lobules and alveoli where milk is produced, as well as the ductile system, leading to 9 to 15 milk duct openings in the nipple. During pregnancy, the breasts enlarge as lobules mature and differentiate in response to estrogen, placental lactogen, prolactin, and progesterone. The nipples darken, and the surrounding areolas enlarge. In the first 24 hours after delivery, only a small volume of colostrum, approximately 40 to 50 mL total, is produced. By 3 to 4 days after delivery, however, increased milk production, termed lactogenesis stage 2, commences. This occurs as estrogen and progesterone levels drop and prolactin, from the anterior pituitary, is increased in response to nipple stimulation. Additionally, oxytocin is released from the posterior pituitary and causes contraction of myoepithelial cells, which squeeze milk from the alveoli. Although initial production of milk is not dependent on newborn suckling, the more the neonate feeds and the more often the breast is effectively emptied, the more milk is produced. If milk is not removed, an autocrine hormone in milk called feedback inhibitor of lactation acts locally within each breast to inhibit milk production. Early effective removal of colostrum, ideally starting within 1 hour of delivery, speeds the arrival of increased milk volume, and frequent milk removal increases supply in the weeks that follow.

Benefits of Breastfeeding

For the baby, the benefits of breastfeeding are myriad. Studies have demonstrated that breastfed infants have a decreased incidence and severity of infectious illnesses, including diarrhea, respiratory infections, otitis media, bacterial meningitis, and urinary tract infections. They have lower rates of hospitalization and mortality. The incidence of otitis media is 100% higher in formula-fed infants than exclusively breastfed infants. Studies have also demonstrated better performance on cognitive testing among children who were breastfed as infants. Among preterm infants fed human milk, the incidence of necrotizing enterocolitis is also significantly reduced. Breastfeeding in infancy also reduces the later incidence of atopy, allergies, asthma, childhood obesity, type 2 diabetes, and even childhood cancer. Decreased rates of sudden infant death syndrome (see Chapter 72) have also been documented. All these benefits are increased by increasing the length and exclusivity of breastfeeding.

For the mother, an immediate benefit to breastfeeding is oxytocin-induced decreased postpartum blood loss and enhanced mother-infant bonding. Lactation amenorrhea may serve subsequently as birth control. Breastfeeding has also been associated with quicker return to prepregnancy weight as well as decreased risk of breast cancer, ovarian cancer, diabetes, hypertension, heart disease, and osteoporosis. Some evidence suggests that breastfeeding decreases the risk of postpartum depression.

Societal benefits from breastfeeding include markedly decreased annual health care costs. An estimated savings of $10.5 billion annually could be generated if 80% of American families breastfed exclusively for the first 6 months after birth.

Barriers to Breastfeeding

Many studies have evaluated barriers to breastfeeding in the United States. Understanding these barriers is essential to improving breastfeeding rates. With effective physician, nursing, and peer support, most mothers should be able to breastfeed successfully. One of the most important barriers is the lack of knowledge of pregnant women about the benefits of feeding mother’s milk. Education beginning at the first prenatal visit is vitally important.

Some mothers report feeling uncomfortable breastfeeding in public. Identifying this issue and helping these mothers feel more supported or find privacy when they need it can help them succeed with breastfeeding. Currently, laws exist in all 50 states and the District of Columbia that protect a mother’s right to breastfeed in public.

Many new mothers have poor family support for breastfeeding, and it is necessary to include the entire family in breastfeeding counseling. The mother will not be successful if her family is encouraging her to use formula.

Some mothers find that their place of employment does not make accommodations for a breastfeeding mother. It may be that the workplace needs to be reminded of laws promoting breastfeeding in the workplace. The Patient Protection and Affordable Care Act includes a provision that the workplace must provide adequate break time and a private place for nursing mothers to pump for up to 1 year. Some states offer additional protections.

Hospitals may have practices or policies that interfere with successful breastfeeding, including high rates of cesarean section or no rooming-in policy. Physicians should work with their hospitals to minimize these potential barriers. Some medical professionals become barriers to exclusive breastfeeding because they lack the knowledge to properly manage problems as they arise.

Contraindications

Absolute contraindications to breastfeeding are few. The neonate with galactosemia type I as detected by newborn screening and who therefore is unable to metabolize lactose or galactose may not exclusively breastfeed. Newborns can also inherit defects in protein metabolism that may necessitate a special diet, precluding breastfeeding. In most states, newborn screening now includes testing for most of these metabolic disorders.

Maternal infections prohibiting breastfeeding include active, untreated tuberculosis and HIV. Additionally, if herpetic vesicles are present on the breast, the mother should not breastfeed from that breast.

Medications and Drugs of Abuse

Most medications are safe for a mother to use while breastfeeding, and the risk to the newborn or infant of not breastfeeding often outweighs the risk of exposure to subclinical doses of the medication in human milk. Each medicine should be reviewed for potential effects on the infant or possible negative effects on milk supply. The LactMed App is an excellent free resource (https://toxnet.nlm.nih.gov/help/newtoxnet/lactmedapp.htm). Chemotherapeutic agents, antimetabolites, radioactive isotopes, and drugs of abuse are all contraindicated for breastfeeding. However, a mother with a history of drug use may benefit from breastfeeding provided her toxicology results are closely monitored and are negative.

The 2018 American Academy of Pediatrics clinical report on marijuana use during pregnancy and breastfeeding states that because the potential risks of infant exposure to marijuana metabolites are unknown, women should be informed of the potential risk of exposure during lactation and encouraged to abstain from using any marijuana products while breastfeeding. Although marijuana is legal in some US states, pregnant and breastfeeding women who use marijuana may be subject to child welfare investigations if they have a positive marijuana screening result.

Breastfeeding Management

The management of breastfeeding should begin in the prenatal period. The US Preventive Services Task Force endorses promotion and support for breastfeeding at all health care encounters. The pregnant woman should be educated by her pediatrician and obstetrician on the benefits of breastfeeding. Her history should be reviewed for potential contraindications. If none exist, she should be encouraged to breastfeed. If she commits to breastfeeding before the baby is born, she is more likely to be successful. Involving her partner in these discussions has also been shown to improve breastfeeding success rates.

At the time of delivery, if there are no complications, the neonate should be dried and placed skin to skin on the mother’s abdomen or chest for warmth and contact. Initial Apgar scores can be assigned during this process. The newborn will find his or her way to the breast and latch on. This early breastfeeding experience greatly facilitates further breastfeeding. The neonate should not be separated from the mother except for medical reasons. If an infant or mother is not medically stable enough to breastfeed immediately after birth, hand expression should be initiated within 1 hour of delivery.

During the hospital stay, the newborn should breastfeed on demand on both breasts for as long as she or he wants. Hospital policies for rooming-in greatly facilitate breastfeeding. Generally, the neonate should nurse at least 8 times a day. A healthy full-term newborn has no medical need for formula supplements. Without pacifiers or supplemental feeds, the neonate will learn to breastfeed more quickly. The mother should be counseled on appropriate latch-on, positioning of the newborn, and manual expression of milk. Breastfeeding support should be available from all involved hospital staff, and a certified lactation consultant can be quite helpful. Early supplementation with expressed colostrum should be started for infants who are at high risk of breastfeeding problems, such as those who are preterm, multiples, weigh less than 2.7 kg (<6 lb), or feeding poorly for 12 hours, as well as for those whose mothers had cesarean section, prior breast surgery, or previous breastfeeding problems. Early supplementation with expressed colostrum can decrease excessive weight loss in the infant.

Urine and stool output can be a reliable indicator of the success of breastfeeding. A successful breastfeeding neonate should urinate 3 times a day and pass stool 3 to 4 times a day by 3 to 5 days of age. By day 5 to 7 of age, the neonate should urinate 4 to 6 times a day and pass 3 to 6 stools a day. Weight loss should be monitored and should not exceed 10% of birth weight without further evaluation. Mothers whose newborns are taken to the neonatal intensive care unit must be helped with pumping or hand expressing their breasts within the first hour after delivery. By encouraging initial and frequent expression of milk, a mother’s milk supply can be established even when her newborn cannot directly nurse.

During the first 6 months after birth, the only supplement to breastfeeding that is needed is vitamin D 400 IU daily started in the first few days after birth to prevent rickets. Intramuscular vitamin K to prevent hemorrhagic disease of the newborn, application of ophthalmic antibiotic ointment or silver nitrate to prevent gonorrheal infections, and hepatitis B vaccination are administered to all newborns shortly after birth (see Chapter 23).

After hospital discharge, the breastfeeding newborn should be seen by the physician at day 3 to 5 of age and again at 2 weeks of age to support breastfeeding. Early assessment may prevent many breastfeeding problems and enables the physician to intervene early if problems arise, thereby helping to prevent discontinuation of breastfeeding. New mothers need encouragement and reassurance. At each visit, the neonate should be assessed for weight, feeding schedules, voiding and stooling patterns, and jaundice. The mother’s breasts should be examined for fullness, engorgement, and nipple trauma. A feeding should be observed. Mothers who are giving formula supplementation in the first weeks need help improving milk transfer and weaning formula supplements. Referral to a lactation specialist and a follow-up appointment in several days is essential.

The infant should exclusively breastfeed until 6 months of age. At that time an iron source is needed, and iron-fortified cereal can be given with a gradual introduction of other pureed foods. The recommendation is that breastfeeding continue until at least 1 year of age or as long as the mother and infant desire.

If a mother plans to return to work, she should be counseled to initiate exclusive breastfeeding and wait until the infant is approximately 4 weeks of age before introducing a bottle of expressed milk. When the mother is separated from the infant, she should pump her breasts at regular intervals. The milk can be stored at room temperature for 4 hours, in the refrigerator for up to 4 days, or in the freezer for up to 6 months (ideal) or even 12 months (acceptable) for later use. Generally, milk should be stored in 2- to 4-ounce bags or containers that are labeled with the date of expression. When the mother is back with the infant, she should put the infant to breast at the usual interval rather than using the previously expressed milk. Many mothers can work and breastfeed well past a child’s first birthday.

Sometimes pediatricians are consulted about weaning the breastfed infant. There is no age at which weaning must occur, and in many cultures toddlers nurse until age 3 to 4 years. Although some infants readily give up the breast, others are more reluctant to do so. Lactation consultants may be a valuable resource at this time.

Potential Problems

Attachment

Latching-on is the first step that is essential for successful breastfeeding. Getting some infants to latch may be difficult initially because of sleepiness or fussiness when attempts are made. It is best to start feedings when the infant exhibits early feeding cues, such as licking lips or bringing hands to the mouth. Placing the infant skin to skin in a vertical position on the mother’s chest while she is leaning back can stimulate reflexive infant feeding behaviors. Infants can often maneuver themselves to the nipple with a little help if they are lying on top of their mother as she reclines in bed. The newborn should be positioned with 1 hand on each side of the breast and the chin touching the breast and the nipple near the baby’s nose. This allows the infant to get as much of the areola in the mouth as possible. Causes of poor latching include poor positioning, inverted or flat nipples, ankyloglossia (ie, tongue-tie), small mandible, engorgement, or nipple confusion (ie, preference for firm bottle nipples or pacifiers). Management may consist of help with positioning, frenot-omy, or use of a supplemental nursing system at the breast. A supplemental nursing system is a small tube connected to a syringe or bottle that is slid into the infant’s mouth after the infant is latched onto the breast to give a supplement of expressed milk or formula while the infant breastfeeds. This can provide flow to stimulate sucking in a sleepy infant. Occasionally nipple shields are used, but these may limit nipple stimulation and cause problems with milk supply. Thus, mothers who are given shields should be followed closely and encouraged to express milk after feedings to ensure a strong supply. In any instance of difficulty with attachment, hand expression or a pump should be used to ensure frequent effective breast emptying so that milk production continues.

Sore Nipples

Breastfeeding should not be painful. If the mother is experiencing pain, the neonate is probably not latching correctly and may be crushing the nipple with his or her gums. This may cause cracked and even bleeding nipples. If the nipple is being compressed the ducts are compressed as well, resulting in poor milk transfer. The nipple may appear flat or pinched after the feeding. Pediatricians can learn a great deal about the status of breastfeeding by checking a mother’s breasts for fullness and trauma. With a correct latch, neonates have the nipple and a significant portion of the areola in their mouth with their lips flanged outward. If a mother experiences pain, the newborn should be removed from the nipple and attached again. If pain persists, a medical professional should evaluate the mother-infant dyad for problems. Cracked nipples can be treated with lanolin or hydrogel pads and repositioning. Mothers should express their milk if the latch is shallow to avoid engorgement and decreased supply. Expressed milk left to dry on cracked or bleeding nipples has healing properties. In the setting of significant injury, the mother may need to pump the affected breast for 24 hours while the nipple heals. Occasionally sore nipples are secondary to a candidal or bacterial infection, atopic dermatitis, or Raynaud phenomenon (ie, vasospasm). Raynaud phenomenon can be secondary to trauma, tends to be worse when nipples get cold, and often is improved with several days of low heat.

Engorgement/Mastitis

Engorgement may occur in the setting of milk stasis for any reason. The breast appears full, firm, lumpy, and tender. Treatment is to empty the breast, and the newborn or infant is the most effective breast pump. Gentle manual compression along the posterior edge of the glandular tissue may improve emptying. Application of warm packs or taking a hot shower before feeding can be helpful. Sometimes an electric breast pump expedites emptying, softens the breast, and facilitates baby latching. If it is not possible to empty an area of the breast, such as in cases of a prior surgery that has sev-ered some ducts, feedback inhibitor of lactation will decrease and stop milk production in this area. Postpartum engorgement may also be caused in part by interstitial edema and improved by gentle massage toward the axillary lymph nodes.

Left untreated, engorgement may result in mastitis, which is breast inflammation with signs of systemic infection, frequently including fever and body aches. If a mother develops mastitis, she should continue to breastfeed. Emptying the breast is important, but treatment also consists of oral antibiotics and rest. Ineffective treatment of mastitis may result in progression to a breast abscess requiring more invasive treatments, such as serial needle aspiration, drain placement, or incision and drainage. Incisions should be made parallel to ducts to avoid severing them and away from the areola so the baby can continue to latch. In cases of frank pus coming from the nipple, the baby should not breastfeed until the discharge has resolved. The mother should pump the affected breast to empty the milk and support her supply.

Low Supply

The most common reason for early cessation of breastfeeding is perceived low milk supply. Although 95% of women from developed countries are physiologically able to produce sufficient milk, many supplement with formula when it is not medically necessary. Supplementation may be done because of difficulty with latch or unrealistic expectations of newborn behavior causing a lack of confidence. Formula supplementation leads to decreased frequency of breastfeeding, and in time, milk supply decreases if the breasts are not emptied by the baby, a pump, or hand expression.

To encourage exclusive breastfeeding, medical professionals must be able to support a mother’s confidence and ability to breastfeed. They must be able to assess milk transfer as well as baby hydration and weight gain. When supplementation is necessary, medical professionals must enable mothers to express their breasts; often, this milk is the only supplement necessary. Any formula supplements given in the first few days should be of limited volume and should be stopped when mothers experience lactogenesis stage 2. At office visits, if babies have been given formula unnecessarily, physicians must help families by addressing breastfeeding problems and closely following the baby’s weight as supplements are decreased and eliminated. In later months, mothers may express concern over shorter feeding times, thinking that they have less milk when, in fact, infants have become more efficient eaters.

In the baby with poor weight gain, a thorough investigation must be undertaken to determine whether the difficulty stems from a problem with the baby, mother’s milk supply, milk transfer, or some combination of these. It is critical to provide the baby with sufficient calories and protect the mother’s supply with pumping during this time. For mothers who do lack sufficient milk, more frequent and effective emptying of the breast may solve the problem; however, if this is unsuccessful, galactagogues (ie, human milk stimulants) may be useful in some cases.

Hyperbilirubinemia/Dehydration

Ten percent of exclusively breastfed infants born via vaginal delivery and 25% of infants born via cesarean section lose more than 10% of their birth weight. Too often, infants are started on formula supplements just as mothers have increasing milk volume. For this reason, it is important to check a mother’s breasts at each visit and encourage expression of milk at each feeding if an infant requires supplementation. Neonates who lose more than 10% to 12% of their birth weight are at risk for becoming dehydrated and have an increased likelihood of significant jaundice. Increased intake is necessary, and the frequency of feeds should be increased. If a newborn is not latching on well, expressed milk can be given by syringe. Neonates should be closely monitored, and formula can be offered after human milk if milk supply is insufficient. If insufficient supply is the problem, the mother should be assisted in increasing her milk supply. Using a breast pump will increase supply because of increased demand. If the newborn appears significantly jaundiced, serum levels of bilirubin should be obtained. Physiologic jaundice is related to hepatic immaturity with decreased conjugation of bilirubin as well as decreased excretion. Breastfeeding babies tend to have increased levels of unconjugated bilirubin. Increased feeding frequently resolves the problem as hydration status improves and frequency of stooling increases. Occasionally, especially in late preterm neonates, treatment with phototherapy is necessary. Interrupting breastfeeding is neither necessary nor helpful. For a more extensive discussion of jaundice, see Chapter 126.

Resources for the Breastfeeding Mother

Many hospitals and health care organizations have lactation specialists who can assist nursing mothers and answer questions related to lactation. Health facilities may loan or rent electric breast pumps to new mothers to help establish a good supply of milk. Some mothers may choose to purchase such pumps, especially if they are planning to continue to breastfeed after returning to work. Breast pumps usually are covered by health insurance.

Access to information can also be obtained through the internet, community agencies, or international and national organizations such as La Leche League International (www.lalecheleague.org) and the Special Supplemental Nutrition Program for Women, Infants, and Children. Such agencies provide a resource to the health care professional in assisting mothers with breastfeeding.

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