Maternal and economic benefits of breastfeeding

INTRODUCTION — Breastfeeding offers short- and long-term health and developmental benefits to children and their mothers [1]. The benefits to the children are in part explained by the fact that human milk contains a constellation of nutrients and other bioactive substances that protect against infectious and noncommunicable diseases. Maternal benefits include reduction of the risk for breast, ovarian, and endometrial cancer, as well as type 2 diabetes mellitus. These effects may be related to the complex hormonal mechanisms involved in the regulation of breast milk production in response to infant suckling [2]. Given these benefits of breastfeeding on infant and maternal health, it is not surprising that there are also strong economic benefits to the family and society.

Women require support from all of society to fulfill their breastfeeding plans [3]. Decisions about initiating and maintaining breastfeeding are influenced by the unique challenges and supports of the mother, infant, and family. These considerations and strategies for shared decision-making, addressing obstacles, and providing support are discussed in separate topic reviews. (See "Breastfeeding: Parental education and support" and "Common problems of breastfeeding and weaning".)

The maternal and economic benefits of breastfeeding will be reviewed here. The benefits of breastfeeding for the infant are discussed separately. (See "Infant benefits of breastfeeding".)

MATERNAL BENEFIT — Breastfeeding provides health benefits to the mother during lactation, as well as beyond the breastfeeding period, as outlined in a literature review from the Agency for Healthcare Research and Quality (AHRQ) [4].

Benefits during lactation — Benefits to the mother during lactation include:

Reduced risk of postpartum blood loss — Through the action of oxytocin, initiation of breastfeeding soon after delivery helps the uterus to return to its normal size sooner after birth and lowers the risk of excessive postpartum blood loss [5].

Delay in resumption of ovulation — Exclusive breastfeeding significantly delays the return of ovulation after giving birth; the hormonal biologic mechanism by which it happens has been well elucidated [6]. The timing of resumption of ovulation varies and depends in part on the frequency of breastfeeding. Even among exclusively breastfeeding women, return of ovulation varies and is not predictable. Therefore, counseling regarding contraception should be offered promptly, ideally prenatally and during the first few days or weeks after delivery. (See "Overview of the postpartum period: Normal physiology and routine maternal care", section on 'Contraception' and "Contraception: Postpartum counseling and methods".)

The association between short interpregnancy interval and adverse pregnancy outcomes is discussed separately. (See "Interpregnancy interval: Optimizing time between pregnancies", section on 'Associations between birth spacing and pregnancy outcome'.)

Postpartum depression and weight change (no clear effect) — Evidence is insufficient to determine the association of breastfeeding with postpartum depression or weight change:

●Postpartum depression – Some but not all studies have found an association between shorter breastfeeding duration or exclusive breastfeeding and risk of postpartum depression [7]. When an association is found, the causal direction is unclear [4,7,8]. (See "Postpartum blues" and "Postpartum unipolar major depression: Epidemiology, clinical features, assessment, and diagnosis", section on 'Risk factors'.)

●Postpartum weight change – Studies are inconclusive or have conflicting results regarding associations between breastfeeding and postpartum weight change [4]. This uncertainty may be due to differences in measurement time points, the many interrelated psychosocial and behavioral variables that influence the decision to breastfeed, and the behaviors that influence body weight. (See "Maternal nutrition during lactation", section on 'Effects of lactation on the mother'.)

Long-term benefits — Breastfeeding and longer duration of breastfeeding are associated with lower rates of breast cancer, epithelial ovarian cancer, hypertension, and type 2 diabetes but not bone fractures, as outlined in a systematic review [4]. The evidence for these associations is summarized below.

Cancer — Breastfeeding has been shown to reduce the risk of breast, ovarian, and endometrial cancer. These associations are discussed elsewhere in the program. (See "Epithelial carcinoma of the ovary, fallopian tube, and peritoneum: Incidence and risk factors", section on 'Breastfeeding' and "Factors that modify breast cancer risk in women", section on 'Breastfeeding' and "Endometrial carcinoma: Epidemiology, risk factors, and prevention", section on 'Other potential protective factors'.)

Cardiovascular disease — Breastfeeding appears to have some long-term cardioprotective effects, perhaps because it helps postpartum women revert to the nonpregnant metabolic state, as indicated by a healthier cardiovascular risk profile compared with the pregnant metabolic state [9,10]. Supportive evidence includes a longitudinal cohort study of Black women in the United States, which found that a history of breastfeeding was associated with reduced risk of hypertension at age 40 to 49 years [11]. This association was stronger among those with longer cumulative breastfeeding durations, especially among those who had breastfed for ≥24 months. Similarly, a systematic literature review of 19 studies from high-income countries reported a protective effect of breastfeeding against hypertension that persisted in long-term follow-up [12]. Consistent with this finding, several studies have found a higher risk of hypertension among women who never breastfed compared with their counterparts who breastfed [13-15].

Accordingly, breastfeeding duration is also associated with reduced cardiometabolic risk. This was shown in a meta-analysis of eight studies from resource-abundant countries, in which any breastfeeding was associated with reduced risk for all cardiovascular outcomes (cardiovascular disease, coronary heart disease, stroke, and fatal cardiovascular disease) [16]. The risk reduction was correlated with longer lifetime breastfeeding duration, up to 12 months. A subsequent study in nearly 20,000 women with gestational diabetes or type 2 diabetes confirmed similar benefits in this high-risk group [17]. However, further research is needed to confirm the link between breastfeeding and cardiovascular disease and how it may be modified by parity and maternal age [4].

Type 2 diabetes mellitus — Lactation is associated with improved glucose tolerance and insulin sensitivity [18,19]. Moreover, breastfeeding is associated with significantly reduced maternal risk of developing type 2 diabetes later in life [20-22]. This protection seems to be greater among those women with longer breastfeeding durations; two meta-analyses of four studies from high-income countries found that women with the longest breastfeeding durations had a 30 percent decrease in their relative risk (RR) of developing type 2 diabetes compared with women who did not breastfeed [23]. A 9 percent decrease in risk of type 2 diabetes was reported for each 12-month increase in lifetime breastfeeding duration, after adjustment for other risk factors for diabetes including physical activity, body mass index (BMI), smoking, alcohol use, income, education, parity, and family history. Similar findings were found in several large cohort studies. A multicenter, longitudinal cohort study conducted among Black and White women (n = 1238) found that longer breastfeeding duration was strongly associated with a 25 to 47 percent reduction in diabetes incidence after controlling for gestational diabetes, lifestyle behaviors, weight gain, and other clinical and sociodemographic characteristics [24]. Similarly, a prospective cohort study conducted in New York City found that at three years postpartum, the women that breastfed for ≥12 months had a lower prevalence of prediabetes and diabetes (12.5 percent) compared with those who breastfed for ≤3 months (21.4 percent) or for 3 to 12 months (25.7 percent) [25]. Breastfeeding for ≥12 months was inversely associated with prediabetes/diabetes (odds ratio [OR] 0.37, 95% CI 0.18-0.78), and was also associated with lower fasting glucose, improved oral glucose tolerance, and improved indices of insulin sensitivity.

Similar findings have been reported among women with gestational diabetes mellitus (GDM). A two-year prospective cohort study of women with GDM found that higher intensity and longer breastfeeding duration were associated with a lower incidence of type 2 diabetes [26]. A systematic review and meta-analysis of 13 cohort studies found a significantly lower risk for developing type 2 diabetes among women with a history of GDM who breastfed (RR 0.66, 95% CI 0.48-0.90) compared with those who had not breastfed [27]. Another systematic review and meta-analysis of nine studies also found that among women with GDM, exclusive breastfeeding for at least six to nine weeks was associated with a lower risk of type 2 diabetes compared with those who had not breastfed (OR 0.42, 95% CI 0.22-0.81) [28].

Osteoporosis (no clear effect) — Evidence from clinical and epidemiologic studies indicate that lactation generally does not have long-term adverse effects on bone health. However, more studies are needed to assess the effects of extended breastfeeding duration (>18 months) on bone health.

Bone mineral density (BMD) tends to decrease during lactation because skeletal calcium is the main source of calcium for breast milk production [29,30]. As an example, among exclusive breastfeeding mothers, mean BMD losses from lumbar spine can be between 5 to 10 percent [30].

However, BMD is typically restored to basal levels post-weaning, as shown in a variety of mineral homeostasis studies conducted in animals and humans [29,30]. These findings are generally, but not always, consistent with epidemiologic studies of osteoporosis and fractures. As examples, a meta-analysis of six studies from low- and high-income countries assessing the association between breastfeeding and femoral bone mass concluded that there were no clear associations between breastfeeding and osteoporosis [6]. Similarly, prospective analysis from a cohort study of postmenopausal women (50 to 79 years old) living in the United States found that lifetime lactation history was not associated with fracture risk or bone density [31]. Another cohort study conducted among pre- or perimenopausal women (42 to 53 years old) also concluded that lactation has little or no association with bone strength or fracture risk in long-term follow-up [32]. By contrast, a cross-sectional study from Korea among 1222 postmenopausal women concluded that prolonged breastfeeding (≥19 months) was significantly associated with lower BMD in the lumbar spine and higher prevalence of osteoporosis [33]. Conversely, a literature review that included 31 studies with diverse designs and sample sizes among pre- and postmenopausal women concluded that lactation may be associated with higher BMD, but this effect may be modulated by breastfeeding duration and parity [34].

ECONOMIC BENEFIT — Breastfeeding is associated with substantial economic benefits to both the family and society. The economic advantages have been estimated based on sound economic models applied globally [35] and in the United States [36]. These findings provide an additional economic rationale for programs that protect, promote, and support breastfeeding in the United States and worldwide [37,38].

The economic costs of not breastfeeding come from a combination of sources, including direct health care costs to treat maternal and child morbidity, lost economic productivity due to premature mortality, and costs associated with the decreases in cognitive development of the child.

Societal benefit — A comprehensive global analysis estimated the following number of deaths could be prevented annually if all infants were breastfed following the World Health Organization (WHO) and United Nations Children's Fund (UNICEF) recommendations, which include exclusive breastfeeding for six months and continued breastfeeding until at least two years of age [35]:

●595,379 deaths due to diarrhea and pneumonia among children 6 to 59 months of age

●974,566 cases of childhood obesity

●98,243 deaths due to breast and ovarian cancer and type 2 diabetes

These and other adverse health effects due to lack of optimal breastfeeding practices translate to total estimated global economic losses of USD $341.3 billion per year, which is equivalent to 0.70 percent of the global gross national income (GNI), ranging from 0.25 percent GNI in high-income countries to 1.99 percent GNI in low-income countries. Of this total, $285.4 billion were attributed to cognitive losses, $53.7 billion due to child mortality, and $1.26 billion due maternal mortality. The estimated direct cost to the health care system due to child diarrhea and pneumonia and maternal type 2 diabetes was estimated at $1.1 billion per year. Other studies have also reported a large economic impact of reduced cognition due to suboptimal breastfeeding practices [1,35,39].

In the United States, a study modeled the impact of breastfeeding on nine pediatric and five maternal diseases in a hypothetical cohort of women 15 to 70 years old and their children from birth to 20 years [36]. The study estimated that there were 3340 annual excess maternal or child deaths attributed to suboptimal breastfeeding. Of these, 78 percent were attributed to maternal myocardial infarction, breast cancer, and diabetes. There were 721 pediatric deaths mainly explained by sudden infant death syndrome (SIDS) and necrotizing enterocolitis. Medical costs related to suboptimal breastfeeding were estimated at $3.9 billion per year, 79 percent of which were due to maternal morbidity. The estimated cost of premature mortality was $14.2 billion annually. This study did not include the large economic benefit of improved cognition attributed to optimal breastfeeding practices. In North America, the annual cost of cognitive losses attributed to not breastfeeding optimally has been estimated at $115 billion, representing 0.6 percent GNI, which was more than 40 percent of the total costs of not breastfeeding in that analysis [35].

Breastfeeding also has substantial environmental benefit by avoiding the extensive use of water needed for infant formula production and consumption; plastic, paper, and metal waste from bottles and infant formula packaging materials; and carbon emissions associated with producing, packaging, transporting, and preparing the formula [39,40]. One study estimated that optimal breastfeeding in the United Kingdom alone would save carbon emissions equivalent to taking 55,000 to 77,500 cars off of the road each year [41,42].

Familial benefit — The savings in health costs and increased productivity attributable to breastfeeding ultimately translates to an economic benefit to the individual family, which varies widely by population. In addition, the family saves the cost of infant formula, which amounts to approximately $1200 to $2000 annually for one infant in the United States [43,44]. In a global analysis, the cost of formula was estimated to be an average of 6.1 percent of a household's wages, with a higher percentage among low-income families or in low- and middle-income countries [35].

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Breastfeeding and infant nutrition".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topics (see "Patient education: Pumping and storing breast milk (The Basics)" and "Patient education: Deciding to breastfeed (The Basics)")

●Beyond the Basics topics (see "Patient education: Pumping breast milk (Beyond the Basics)" and "Patient education: Deciding to breastfeed (Beyond the Basics)")

SUMMARY

●Short-term maternal health benefits – Maternal benefits of breastfeeding during lactation include accelerated uterine recovery, which reduces the risk of postpartum blood loss. Breastfeeding also prolongs the state of anovulation, with some benefits for contraception and associated maternal and fetal benefits of avoiding a short interpregnancy interval. Nonetheless, breastfeeding should not be considered a reliable means of contraception. (See 'Benefits during lactation' above.)

●Long-term maternal health benefits – Long-term maternal benefits of breastfeeding include reduction in the risk for breast cancer, ovarian cancer, endometrial cancer, cardiovascular disease, and developing type 2 diabetes during the years after childbirth. There is no clear effect of breastfeeding on the risk of osteoporosis. (See 'Long-term benefits' above.)

●Economic benefits – Breastfeeding decreases out-of-pocket expenditures for families by avoiding the expense of purchasing formula and by reducing health care costs for mother and infant. (See 'Economic benefit' above.)

●Societal benefits – The health benefits for mother and infant translate to significant economic benefits for society by reducing maternal and child morbidity and mortality and the associated health care costs, reducing productivity losses due to premature mortality, and improving economic productivity through its positive impact on cognitive development. These economic benefits provide an additional rationale for programs that protect, promote, and support breastfeeding in the United States and worldwide. (See 'Societal benefit' above.)

●Other factors – Decisions about initiating and maintaining breastfeeding also depend on the unique challenges and supports of the mother, infant, and family. These considerations and strategies for shared decision-making, addressing obstacles, and providing support are discussed separately. (See "Breastfeeding: Parental education and support" and "Common problems of breastfeeding and weaning".)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Richard J Schanler, MD, who contributed to earlier versions of this topic review.