Breastfeeding

[5][10]: 83  Long-term benefits for the mother include decreased risk of breast cancer, cardiovascular disease, diabetes, metabolic syndrome, and rheumatoid arthritis.

The first stage takes place during pregnancy, allowing for the development of the breast and production of colostrum, the thick, early form of milk that is low in volume, but rich in nutrition.

These changes, collectively known as Lactogenesis I, are directed by hormones produced by the placenta and the brain, namely estrogen, progesterone, prolactin, which gradually increase throughout the pregnancy, and result in the structural development of the alveolar (milk-producing) tissue and the production of colostrum.

[10]: 27–34 [40] Produced during pregnancy and the first days after childbirth, colostrum is rich in protein and Vitamins A, B12 and K, which supports infants' growth, brain development, vision, immune systems, red blood cells, and clotting cascade.

[10]: 34–47  Colostrum also helps to seal the infants gastrointestinal tract from foreign substances and germs, which may sensitize the baby to foods that the mother has eaten and decrease the risk of diarrheal illness.

[47]: 502–545  Kangaroo Care stabilizes newborn premature infants' vital signs, such as their heart rate, providing a naturally warm environment that helps them regulate their temperature.

Due to low availability and high cost of donor breastmilk, the AAP recommends prioritizing the use of the milk for infants born with a weight of less than 1500g (approximately 3lb 5oz), as it is helpful in decreasing rates of the severe intestinal infection, necrotizing enterocolitis, in this population.

[100][101] La Leche League and Toronto Public Health offer several techniques to use during pregnancy or even in the early days following birth that may help to bring a flat or inverted nipple out.

In 2016 a large review of studies reported that the use of a pacifier beginning at birth or after lactation was established did not significantly affect the duration of exclusive and partial breastfeeding up to four months of age.

[10]: 34–47 [106][107][108][109] The Academy of Breastfeeding Medicine and the Australian Dental Association have raised concern over the growing trend of oral tie surgeries, due to evidence for benefit being low-quality, inconsistent, or unsupported.

[10]: 55  Finally, milk "coming in" can create an uncomfortably full feeling, which combined with the aforementioned fluid accumulation in the breast tissue, can cause severe pain.

One study found that 15% of healthy first-time mothers had low milk supply 2–3 weeks after birth, with secondary causes accounting for at least two-thirds of those cases.

[40] Jaundice, or yellowing of the skin and eyes, occurs when bilirubin, a byproduct of the breakdown/recycling of red blood cells, builds up in the newborn's bloodstream faster than the liver can break it down and excrete it through the baby's urine and stool.

[47]: 411–313  Mothers who do have an isolated breast infection caused by Mycobacterium tuberculosis, termed tuberculous mastitis, should not feed their infants with their own breastmilk, even if it is fed by bottle.

[146] The CDC advises that breastfeeding is safe to continue as long as the breasts are clear of lesions, also emphasizing that if pumping or hand expressing milk, proper hand-hygiene should be used to minimize transfer.

[164][10]: 105–109 If a parent is concerned with a possible milk contaminant, they can express and save the breastmilk until they are able to consult with a lactation specialist or another medical professional trained in breastfeeding medicine.

WHO states, "Breast milk is the ideal food for the healthy growth and development of infants; breastfeeding is also an integral part of the reproductive process with important implications for the health of mothers.

[192] Breast milk contains several anti-infective factors such as bile salt stimulated lipase (protecting against amoebic infections) and lactoferrin (which binds to iron and inhibits the growth of intestinal bacteria).

[202] The World Health Organization reports that babies who receive no breast milk are almost six times more likely to die by the age of one month than those who are partially or fully breastfed.

[205] In children who are at risk for developing allergic diseases (defined as at least one parent or sibling having atopy), atopic syndrome can be prevented or delayed through 4-month exclusive breastfeeding, though these benefits may not persist.

This backward flow may introduce the baby's saliva into the mammary gland, potentially prompting the mother's body to produce tailored immune responses in her breast milk to meet the infant's specific needs.

Breast milk of healthy human mothers who eat gluten-containing foods presents high levels of non-degraded gliadin (the main gluten protein).

[185][186] A 1998 study suggested that breastfed babies have a better chance of good dental health than formula-fed infants because of the developmental effects of breastfeeding on the oral cavity and airway.

Research done in the US shows that information about breastfeeding is rarely provided by a women's obstetricians during their prenatal visits and some health professionals incorrectly believe that commercially prepared formula is nutritionally equivalent to breast milk.

[255] Prior breast reduction surgery is strongly associated with an increased probability of low milk supply due to disruption to tissues and nerves.

[201][259] Some substances in the mother's food and drink are passed to the baby through breast milk, including mercury (found in some carnivorous fish),[260] caffeine,[261] and bisphenol A.

[265] Women with polycystic ovary syndrome, which is associated with some hormonal differences and obesity, may have greater difficulty with producing a sufficient supply to support exclusive breastfeeding, especially during the first weeks.

[292] While laws in the U.S. were passed in 2010 which required that nursing mothers who had returned to work be given a non-bathroom space to express milk and a reasonable break time to do so, as of 2016 the majority of American women still did not have access to both accommodations.

[308][309][310][311] In addition to this, there is also the moral question as to what degree the state or medical community can interfere with a person's self-determination: for example in the United Arab Emirates the law requires women to breastfeed babies for at least 2 years and allows husbands to sue them if they do not.

[346] Breastfeeding research continues to assess prevalence, HIV transmission, pharmacology, costs, benefits, immunology, contraindications, and comparisons to synthetic breast milk substitutes.