Chapter II.2. Breastfeeding
Barbora Kadecka, MD
Vanessa M.P. Freitas
November 2022

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A 4-day old exclusively breastfed infant born at 39w gestational age (GA) is seen at your clinic for nursery follow up. Prenatal history is unremarkable. The infant was born via uncomplicated vaginal delivery to a 25-year-old healthy primipara.

The infant is being nursed every two to three hours, has six to eight voids, and about four yellow seedy stools per day. Obtained review of systems is positive for latching difficulties. The mother shares with you her breasts have been swollen and tense. She complains of nipple pain with latching and noticed some nipple injuries with bleeding. She is considering starting formula supplementation as she is worried her infant is not getting enough milk.

Initial measurements in the office show an increase in weight compared to discharge weight from the nursery. On exam, the infant is well hydrated and mildly jaundiced with otherwise normal physical findings.

You reassure mother that her baby is doing well; commending her on choosing to breastfeed despite her discomfort. You then explain that she is very likely experiencing engorgement, which is making it more difficult for her baby to achieve a deep latch causing her pain and nipple injuries. You provide reassurance that this is likely to resolve within a two days while also emphasizing the importance of continuing breastfeeding and expressing milk to prevent clogged ducts and mastitis. You review the technique of reverse pressure which may help her newborn to latch on deeper and you advise mother to apply cold compresses for comfort and/or consider pain medication such as ibuprofen which is safe in breastfeeding mothers for pain relief. Your guidance is much appreciated. Two days later you call the family to follow up and you discover motherís symptoms have largely improved. She and her baby are doing well, and she plans to continue to exclusively breastfeed.

Pediatricians play a critical role in initiation and successful continuation of breastfeeding and should therefore be well trained to provide appropriate education and support to breastfeeding mothers. Education on the benefits of breastfeeding ideally begins prior to birth and continues throughout the peripartum period. Exclusive breastfeeding is recommended for the first 6 months of life and as long as mutually desired by mother and child for 2 years or beyond (1). In recent years, research has continued to validate the health benefits of breastfeeding for both mothers and infants. In mothers, breastfeeding was found to be associated with reduced postpartum bleeding, lower incidence of postpartum depression as well as long term health including decreased maternal diabetes mellitus, hypertension, and reduction of risk for breast and ovarian cancer. Breastfed infants have a lower incidence of sudden infant death syndrome (SIDS), diarrhea, necrotizing enterocolitis, otitis media, and respiratory infection in addition to lower incidences of allergic disease, certain autoimmune diseases, and obesity during childhood and adolescence. Furthermore, breastfeeding brings social, economic, and psychological benefits by improving mother-infant bonding (1,2).

The Centers for Disease Control and Prevention (CDC) periodically publishes data regarding rates of breastfeeding in the United States with significant differences reported based on sociodemographic factors and culture. The latest available overall rates graphed from 2012 to 2019, showed 2019 breast feeding rates ate 83% for any breastfeeding postnatally, 45% for exclusive breastfeeding through three months of age, and 25% for exclusive breastfeeding through six months of age (3).

The breasts are composed of glandular tissue which is divided into 15 to 25 secretory lobes embedded in adipose tissue and held together by connective tissue known as Cooperís ligaments. Each lobe drains into its own excretory lactiferous duct which then emerges independently in the nipple. During pregnancy, these alveolar secretory units and ducts increase in size, number, and activity to prepare for lactation. Estrogen, progesterone, prolactin, and placental lactogen are the primary hormones responsible for lactation, acting synergistically to stimulate mammary gland ductal growth and epithelial cell proliferation (4).

Although mammary glands are prepared for production of milk by mid pregnancy, its copious secretion does not start until post parturition when progesterone level drops while prolactin remains high. The tactile stimuli from nursing releases oxytocin which facilitates milk ejection (5). Milk production is usually established by two weeks postpartum when maternal hormone levels are becoming stable and milk production continues to be regulated by supply-demand feedback (6).

Human milk contains essential macro- and micronutrients, immunomodulators, and antimicrobial agents for optimal growth and development of newborns (1,7). It is the gold standard for which all formulas attempt to recreate. Lactose, the major carbohydrate in breast milk is metabolized to galactose and glucose, which supply energy for babyís rapid growth. Casein and whey are the major protein components (30% casein, 70% whey). Traditionally, infant formulas are higher in casein, making them more difficult to digest compared to breast milk. The main whey proteins are alpha-lactalbumin, albumin, lactoferrin, lysozyme, and secretory immunoglobulin A (IgA) (8). Over 98% of breast milk fat is triglyceride, accounting for up to 50% of the energy provided from human milk. Lipids are required for the absorption of fat-soluble vitamins and central nervous system (CNS) myelination for proper brain growth and development (9). Lipid concentration is higher in hindmilk (toward the end of feeding) compared to foremilk (at the start of feeding) (6).

Breast milk provides much more than the traditionally considered nutrients, including numerous immunologic factors that promote gut maturity and boost protection against certain diseases (1,7). Colostrum, the first breast milk, contains high amounts of IgA which plays a critical role in gut mucosal immunity by helping to establish healthy normal gut microbiota. Human milk oligosaccharides (HMOs) are bioactive molecules with anti-infective properties against gut pathogens. HMOs are hypothesized to be a key player in protecting infants against necrotizing enterocolitis (7).

There are certain nutrients low in human milk, such as vitamin K and vitamin D. Vitamin K is essential for blood coagulation, but a limited amount is transferred from the placenta to fetus. For this reason, it is recommended for a newborn to receive a single dose of Vitamin K supplementation intramuscularly at birth for the prevention of hemorrhagic disease of the newborn. For vitamin D, a daily supplementation is recommended to all exclusively breastfed infants and infants taking less than 30 ounces of formula per day to avoid inadequate bone mineralization and rickets (1,10).

Zinc and iron are trace elements inadequate in breastfed infants after six months of age. Zinc is an important component of many enzymes and transcription factors. Diets low in zinc can cause impaired immunity and growth. Iron supplementation is important to prevent anemia. Complementary feedings consisting of whole-grain cereals, fish, chicken, and meats should therefore be gradually introduced after six months of age. Iron supplementation before six months of age may be indicated in premature infants (1,9).

A pediatrician who is seeing an infant frequently in the days and weeks following birth can have a positive effect on the breastfeeding journey. Supporting skin-to-skin contact directly postpartum benefits breastfeeding and increases the chances of any or exclusive breastfeeding. Mothers should be seen in the nursery by a trained individual who can assist with latching techniques and instruction regarding recognition of a deep latch. Further education should include expected nursing/feeding frequency, volume/duration of feeds, and changes in elimination based on infantís age (2).

To achieve a deep latch, the infantís body must be in an appropriate position compared to the breast and motherís body. To facilitate a proper latch, mothers are taught the importance of leaning back while bringing the baby to breast allowing for mild neck extension with adequate neck support. To achieve a deep latch, the infantís mouth should be wide open, to cover a larger portion of the areola (not just the nipple itself) and the infantís tongue should be positioned underneath the breast, effectively creating a seal for better milk flow while also causing less trauma to the nipple. The infantís lips should be relaxed and not pinched under the gum line, and the infantís chin touching the breast with baby massaging the areola with their chin rather than suckling at the nipple. This can be achieved when the infantís nose is aligned with the motherís nipple first, followed by allowing a wide opening of infantís mouth prior to bringing baby to the breast. After initial fast suckling, the frequency should slow down, and audible swallows should be heard. After feeding, the nipple can be assessed for pinching which indicates shallow latching and could be painful for mothers (2).

Most pediatricians use the infant's weight gain and elimination pattern (number of wet diapers and stools per day) in addition to physical examination and weight gain, for assessment of successful breastfeeding (2).

In case breastfeeding concerns arise, one should assess the infantís mouth for anatomical variants, evaluation of latch and effective milk transfer, and evaluation of breasts and nipples for clogged ducts, redness, nipple injuries, and other rashes or anatomical variants that may cause difficulty in achieving a deep latch. Additionally, quantification of transferred milk by obtaining and comparing babyís pre- and post- feeding weight can be considered, although a single measurement might not be an accurate representation of the dyadís journey (2).

Engorgement is a common issue of early lactation, occurring typically between days three to five postpartum. It is defined as swelling of the breast and may cause significant discomfort and latching difficulties. Studies evaluating the management of engorgement have not shown that one treatment is superior to others for symptomatic relief, but instead usually a combination of interventions is beneficial, including hand expression of milk, reverse tissue softening, cold/hot compresses, and medications for pain relief (2). Reverse tissue softening is a technique when you apply gentle pressure around the areola (3 to 5 cm around) to soften the tissue, which facilitates successful latching.

Mastitis is defined as inflammation of the breast tissue. It clinically presents as a tender, hot, swollen, wedge-shaped area of the breast associated with systemic symptoms such as fever, chills, or body aches. There are several risk factors for mastitis, including nipple injuries, blisters or blebs, colonization with Staphylococcus aureus, infrequent or missed feedings, latching issues, milk oversupply, illness of mother or baby, and rapid weaning. Breastfeeding is not contraindicated. In fact, more frequent feeding or milk drainage is encouraged as a first-line treatment. Empiric systemic antibiotics are often prescribed for women with symptoms that do not improve within the first 12 to 24 hours and for those that are acutely ill; however, most women do respond to supportive therapy in conjunction with frequent and effective milk removal (2).

Nipple pain remains one of the most common complaints of the early postpartum period. If pain is persistent throughout a nursing session and/or past the first two weeks of breastfeeding, then further evaluation and breastfeeding assistance should be obtained. Most common causes of persistent nipple pain are suboptimal positioning with shallow latch, disorganized suck, excessive milk supply, ankyloglossia, infant biting or jaw clenching at the breast, breast pump trauma, vasospasm, or infection (2).

Ankyloglossia (or tongue-tie) is a condition present at birth that restricts the infantís tongueís range of motion. Based on clinical experience, a presence of restricting tongue-tie in a breast-fed infant can cause poor weight gain, nipple pain and/or trauma, and contribute to an ineffective milk transfer with subsequently premature cessation of breastfeeding. If a tongue-tie is noted on oral assessment, a clinical correlation with breastfeeding difficulties is required to rule out a normal anatomical variant that does not require treatment. Recommending frenotomy (cutting the frenulum under the tongue) is based on the individual assessment of the breastfeeding dyad and all associated symptoms, such as insufficient breast drainage, recurrent mastitis, bottle-feeding difficulties, frequency of feedings, and gassiness (11).

In a limited number of conditions, such as classic galactosemia in infants, maternal active brucellosis, and HTLV (human T-lymphotrophic virus) infection, both breastfeeding and feeding expressed breast milk are contraindicated. For mothers with active untreated tuberculosis or herpes simplex, feeding at the breast is not recommended but expressed milk can be used as these infectious organisms do not pass into breast milk. For HIV positive mothers, the recommendations differ based on geographic location. In developed countries, it is not recommended for HIV positive mothers to breastfeed. However, in the developing world, where mortality of non-breastfed babies is high due to malnutrition and infections, breastfeeding outweighs the risk of acquiring HIV via breast milk. Maternal substance use may not be an absolute contraindication to breastfeeding and further details about the motherís rehabilitation are usually needed to provide recommendations (1).

1. True/False: The AAP supports breastfeeding until the age of two years.

2. Which of the following is NOT a common cause of nipple pain?
   a. Shallow latch
   b. Insufficient milk supply
   c. Ankyloglossia
   d. Breast pump trauma

3. A 6-month-old exclusively breastfed infant receiving vitamin D supplementation is recommended to:
   a. Continue vitamin D
   b. Start complementary feedings
   c. Start complementary feedings and add vitamin K
   d. Start complementary feedings and continue vitamin D

4. True/False: Breastfeeding is contraindicated in lactational mastitis.

1. Meek JY, Noble L, Section on Breast Feeding. Policy Statement: Breastfeeding and the Use of Human Milk. Pediatrics. 2022;150(1):e2022057988. doi: 10.1542/peds.2022-057988
2. Westerfield KL, Koenig K, Oh R. Breastfeeding: Common Questions and Answers. Am Fam Physician. 2018;98(6):368-373.
3. Centers for Disease Control and Prevention. Breastfeeding among US children born 2012 to 2019, CDC National Immunization Survey. Available at: Accessed April 16, 2023.
4. Chapter 22: The Female Reproductive System. In: Mescher AL (ed). Junqueira's Basic Histology Text and Atlas, 16the edition. 2021. McGraw Hill, New York. Online pp:1-43.
5. Alex A, Bhandary E, McGuire KP. Anatomy and Physiology of the Breast during Pregnancy and Lactation. Adv Exp Med Biol. 2020;1252:3Ė7. doi: 10.1007/978-3-030-41596-9_1
6. Boss M, Gardner H, Hartmann P. Normal Human Lactation: closing the gap. F1000Res. 2018;20;7:F1000 Faculty Rev-801. doi: 10.12688/f1000research.14452.1
7. Christian P, Smith ER, Lee SE, Vargas, et al. The need to study human milk as a biological system. Am J Clin Nutr. 2021;113(5):1063Ė1072. doi: 10.1093/ajcn/nqab075
8. Martin, CR, Ling, PR, Blackburn, GL. Review of Infant Feeding: Key Features of Breast Milk and Infant Formula. Nutrients. 2016; 8(5):279.
9. Diab LK, Haemer MA, Primak LE, Krebs NF. Chapter 11: Normal childhood nutrition & its disorders. In: Bunik M, Hay WW, Levin MJ, Abzug MJ (eds). Current Diagnosis & Treatment: Pediatrics, 26th edition. 2022. McGraw Hill, New York. Online page numbers.
10. Simon AE, Ahrens KA. Adherence to Vitamin D Intake Guidelines in the United States. Pediatrics. 2020;145(6):e20193574. doi: 10.1542/peds.2019-3574
11. LeFort Y, Evans A, Livingstone V, et al. Academy of Breastfeeding Medicine Position Statement on Ankyloglossia in Breastfeeding Dyads. Breastfeeding Med. 2021;16(4):278-281. doi: 10.1089/bfm.2021.29179.ylf

Answers to questions
1. True. The AAP recommends exclusive breastfeeding up to six months of age but should be supported until the age of two years.

2. b. A common cause of nipple pain is excessive milk supply. Other common causes include incorrect positioning with shallow latch, disorganized suck, biting or jaw clenching at the breast, breast pump trauma, ankyloglossia, vasospasm, and infection.

3. d. For an exclusively breastfed infant a supplementation with vitamin D is recommended to prevent hypocalcemia and rickets. Introduction to baby foods is recommended at six months of age.

4. False. Frequent feedings or milk drainage is encouraged as a first-line treatment for mastitis.

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