Early breastfeeding is associated with fewer nighttime feeding problems. Early skin-to-skin contact between mother and baby improves breastfeeding outcomes, increases cardio-respiratory stability and decreases infant crying. Reviews from 2007 found numerous benefits. Breastfeeding aids general health, growth and development in the infant. Infants who are not breastfed are at mildly increased risk of developing acute and chronic diseases, including lower respiratory infection, ear infections, bacteremia, bacterial meningitis, botulism, urinary tract infection and necrotizing enterocolitis. Breastfeeding may protect against sudden infant death syndrome, insulin-dependent diabetes mellitus, Crohn’s disease, ulcerative colitis, lymphoma, allergic diseases, digestive diseases and may enhance cognitive development.
The average breastfed baby doubles its birth weight in 5 to 6 months. By one year, a typical breastfed baby weighs about 2½ times its birth weight. At one year, breastfed babies tend to be leaner than formula-fed babies, which improves long-run health.
The Davis Area Research on Lactation, Infant Nutrition and Growth (DARLING) study reported that breastfed and formula-fed groups had similar weight gain during the first 3 months, but the breastfed babies began to drop below the median beginning at 6 to 8 months and were significantly lower weight than the formula-fed group between 6 and 18 months. Length gain and head circumference values were similar between groups, suggesting that the breastfed babies were leaner.
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).
Infants who are exclusively breastfed for the first six months are less likely to die of gastrointestinal infections than infants who switched from exclusive to partial breastfeeding at three to four months.
During breastfeeding, approximately 0.25–0.5 grams per day of secretory IgA antibodies pass to the baby via milk. This is one of the important features of colostrum. The main target for these antibodies are probably microorganisms in the baby’s intestine. The rest of the body displays some uptake of IgA, but this amount is relatively small.
Maternal vaccinations while breastfeeding is safe for almost all vaccines. Additionally, the mother’s immunity obtained by vaccination against tetanus, diphtheria,whooping cough and influenza can protect the baby from these diseases, and breastfeeding can reduce fever rate after infant immunization. However, smallpox andyellow fever vaccines increase the risk of infants developing vaccinia and encephalitis.
Babies who are not breastfed are almost six times more likely to die by the age of one month than those who receive at least some breastmilk.
Infants exclusively breastfed have less chance of developing diabetes mellitus type 1 than those with a shorter duration of breastfeeding. Breastfed infants appear to have a lower likelihood of developing diabetes mellitus type 2 later in life. Breastfeeding is also associated with a lower risk of type 2 diabetes among mothers who practice it.
The protective effect of breastfeeding against obesity is consistent, though small, across many studies. A 2013 longitudinal study reported less obesity at ages two and four years among infants who were breastfed for at least four months.
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.
Other health effects
Breastfeeding may reduce the risk of necrotizing enterocolitis (NEC).
Breastfeeding or introduction of gluten while breastfeeding don’t protect against celiac disease among at-risk children. Breast milk of healthy human mothers who eatgluten-containing foods presents high levels of non-degraded gliadin (the main gluten protein). Early introduction of traces of gluten in babies to potentially induce tolerance doesn’t reduce the risk of developing celiac disease. Delaying the introduction of gluten does not prevent, but is associated with a delayed onset of the disease.
About 19% of leukemia cases may be prevented by breastfeeding for six months or longer.
Breastfeeding may decrease the risk of cardiovascular disease in later life, as indicated by lower cholesterol and C-reactive protein levels in breastfed adult women. Breastfed infants have somewhat lower blood pressure later in life, but it is unclear how much practical benefit this provides.
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. It was thought that with fewer malocclusions, breastfed children may have a reduced need for orthodontic intervention. The report suggested that children with a well rounded, “U-shaped” dental arch, which is found more commonly in breastfed children, may have fewer problems with snoring and sleep apnea in later life. A 2016 review found that breastfeeding protected against malocclusions.
It is unclear whether breastfeeding improves intelligence later in life. Several studies found no relationship after controlling for confounding factors like maternal intelligence (smarter mothers were more likely to breastfeed their babies). However, other studies concluded that breastfeeding was associated with increased cognitive development in childhood, although the cause may be increased mother–child interaction rather than nutrition.