Does breastfeeding contribute to better infant outcomes?

Between 2004 and 2006, the U.S. Department of Health and Human Services launched public service campaigns promoting breastfeeding. One ad featured two pregnant women competing in log-rolling, a water sport where participants balance on a rolling log. Another showed a pregnant woman riding a mechanical bull in a bar, cheered on by a lively crowd. Both ads depicted dramatic falls, followed by the message: "You wouldn’t take risks before your baby is born. Why start after?" A narrator then highlighted the advantages of breastfeeding.

Is bottle-feeding comparable to riding a mechanical bull while pregnant? In the modern mommy wars, where women critique each other’s parenting decisions, it can feel that way. The push for breastfeeding isn’t new—Puritan preacher Cotton Mather advocated for it centuries ago. So why did bottle-feeding gain popularity? In the late 19th century, baby formula emerged, and many American women were convinced they couldn’t breastfeed, partly due to doctors influenced by formula companies [source: Lepore]. Some even thought they were evolving, much like men’s vestigial nipples [source: Lepore]. Additionally, the U.S. has uniquely sexualized breasts, as noted by historian Marilyn Yalom [source: Harmon].

In the 1950s and 1960s, American women began reclaiming their breasts from this evolutionary misconception. La Leche League, a breastfeeding advocacy group, was founded in 1958. Feminists later emphasized that breasts had a purpose beyond male gratification. The 1971 book "Our Bodies, Ourselves" highlighted the health benefits of breast milk over formula. Today, the American Academy of Pediatrics advises exclusive breastfeeding for the first six months of a baby’s life.

When infant formula was first introduced, it was marketed as a scientifically precise way to measure a baby’s nutritional intake. Today, however, scientific evidence strongly supports breastfeeding. What do the latest studies reveal?

Studies on Breast-feeding

Numerous studies indicate that breastfeeding can reduce a child’s risk of various diseases and conditions, including sudden infant death syndrome, respiratory infections, meningitis, pneumonia, diarrhea, ear infections, asthma, diabetes, autoimmune disorders like Crohn’s disease, and leukemia [source: Rabin]. Breastfed infants are also less likely to become obese compared to formula-fed babies [source: Rabin]. The American Academy of Pediatrics estimates that the U.S. could save $3.6 billion annually in healthcare costs if more women breastfed, as it would significantly reduce the need for medical care [source: Harmon]. Breast milk’s unique composition, rich in antibodies, hormones, neuropeptides, and natural opioids, makes it irreplaceable by formula.

Breastfeeding isn’t just beneficial for babies—it also offers advantages for mothers. It aids postpartum recovery by helping the uterus return to its normal size and reducing bleeding. Women who breastfeed have a lower risk of heart attack, stroke, type 2 diabetes, and osteoporosis [source: Rabin]. Additionally, breastfeeding can decrease the risk of ovarian and breast cancer. One study found that women with a family history of breast cancer could reduce their risk to match that of women without such a history through breastfeeding [source: University of North Carolina School of Medicine].

The extensive research on breastfeeding's advantages has even led lawmakers to consider adding warning labels to formula packaging. However, in 2009, Hanna Rosin challenged this notion in "The Atlantic," arguing that breast milk might not be the miraculous solution many claim it to be. The backlash to her article highlighted the intensity of the mommy wars surrounding breastfeeding.

Rosin noted that studies on breastfeeding often show inconsistencies, and those promoting its benefits only establish correlations, not causation. In other words, while breastfed babies may experience positive outcomes, these results could stem from other factors common among breastfeeding mothers. In the U.S., breastfeeding mothers are typically older, more educated, and wealthier, potentially providing their children with additional advantages unrelated to breastfeeding itself.

Moreover, breastfeeding studies often face ethical and methodological challenges. Researchers cannot dictate feeding choices, so they rely on observational studies with self-selected participants. Despite these limitations, one researcher has successfully conducted scientifically rigorous experiments on breastfeeding.

Michael Kramer and PROBIT

In 2001, Michael Kramer from McGill University initiated the Promotion of Breastfeeding Intervention Trial (PROBIT), studying the effects of breastfeeding on 17,000 children in Belarus. Instead of instructing mothers on feeding methods, Kramer observed women who chose to breastfeed from birth. Half of these mothers received guidance from healthcare professionals to breastfeed exclusively for an extended period, while the other half received no such advice. This approach allowed researchers to examine the long-term impacts of breastfeeding.

Kramer’s findings indicate that breastfeeding offers slight advantages over formula feeding but falls short of being the miracle solution many advocates suggest. Extended breastfeeding can lower the risk of eczema and reduce gastrointestinal infections by 40% in the first year of life [sources: Rosin; Kramer et al.]. Notably, breastfed children scored higher on IQ tests, with a 7.5-point increase in verbal intelligence and a 2.9-point increase in non-verbal intelligence by age 6.5 [source: Doheny]. However, Kramer described these effects as modest, emphasizing that a 7.5-point difference doesn’t equate to the gap between genius and intellectual disability [source: Doheny].

Kramer proposed that the benefits of breastfeeding might stem from the close interaction between mother and child rather than the breast milk itself. In a discussion with Hanna Rosin of "The Atlantic," he compared breastfeeding to how rats groom their pups, suggesting the physical act of breastfeeding, not the milk, provides developmental advantages. This distinction is crucial, as many U.S. mothers pump breast milk and bottle-feed their babies. Does this practice diminish the benefits?

Breast or Pump: Does It Matter?

The American Academy of Pediatrics advises exclusive breastfeeding for the first six months of a baby’s life, but many women struggle to meet this goal due to the standard 12-week maternity leave in the U.S. To balance work and breastfeeding, many mothers turn to breast pumps to maintain their milk supply and provide bottles of breast milk. For some women facing breastfeeding challenges, pumping becomes their primary method of feeding their infants.

When breast milk is delivered via a bottle rather than directly from the breast, its benefits may diminish. For instance, research indicates that breastfed babies are less likely to become overweight, as breastfeeding helps mothers recognize when their child is full, preventing overfeeding. A study found that bottle-fed babies, whether given formula or breast milk, were more prone to overeating [source: Temple University]. However, it remains unclear whether the reduced obesity risk is due to breast milk or other factors in the child’s environment.

Another study suggested that breastfed babies handle stress better than bottle-fed infants. Researchers highlighted that this outcome might stem from the close mother-child interaction during breastfeeding, which shapes neural development, rather than the milk itself [source: BMJ Specialty Journals]. Drawing parallels from animal behavior, they reinforced the idea that bonding plays a critical role in these benefits.

Every mother, whether breastfeeding or bottle-feeding, can foster a close bond with her newborn, potentially reaping similar benefits. However, both groups often face societal pressures—bottle-feeding mothers may feel guilt over their choice, while breastfeeding mothers encounter criticism for nursing in public. Ultimately, research shows there’s no definitive right or wrong choice when it comes to feeding a child.