Baby bottle
A baby bottle, nursing bottle, or feeding bottle is a bottle with a teat (also called a nipple in the US) attached to it, which creates the ability to drink via suckling. It is typically used by infants and young children, or if someone cannot (without difficulty) drink from a cup, for feeding oneself or being fed. It can also be used to feed non-human mammals, whose mother cannot feed their young or mammals which have no mother.
Hard plastic is the most common material used, being transparent, light-weight, and resistant to breakage. Glass bottles have been recommended as being easier to clean, less likely to retain formula residues,<ref name="Chen">Template:Cite journal</ref> and relatively chemically inert.<ref name="Everts">Template:Cite journal</ref> Hybrid bottles using plastic on the outside and glass inside have also been developed.<ref name="4Types">Template:Cite web</ref> Other materials used for baby bottles include food-grade stainless steel and silicone rubber.<ref name="HongKong">Template:Cite book</ref><ref name="Gimme">Template:Cite web</ref><ref name="Best">Template:Cite web</ref>
Baby bottles can be used to feed expressed breast milk, infant formula,<ref name="More"/> or pediatric electrolyte solution. A 2020 review reports that healthy term infants, when breastfeeding or bottle-feeding, "use similar tongue and jaw movements, can create suction and sequentially use teat compression to obtain milk, with minimal differences in oxygen saturation and SSB patterns" (suck–swallow–breath patterns).<ref name="Kotowski"/> Sick or pre-term babies may not be able to breastfeed or take a bottle effectively and may need specialized care.<ref name="CHOP">Template:Cite web</ref><ref name="More">Template:Cite book</ref>
The design characteristics of the bottle and teat have been found to affect infant feeding and milk intake. Interactions between the infant and the caregiver feeding them affect the infant's milk intake during feeding. Whether the caregiver or the infant controls the feeding appears to affect the infant's ability to learn to self-regulate their milk intake.<ref name="Kotowski">Template:Cite journal</ref> Proper cleaning and sterilization of bottles are recommended to avoid bacterial contamination and illness,<ref name=":0">Template:Cite web</ref> particularly in areas where water quality and sanitary conditions are not good.<ref name=":0" />
Design considerations
A typical baby bottle has four components: the first is the main container or body of the bottle. A teat, or nipple, is the flexible part of the bottle that the baby will suck from, and contains a hole through which the milk will flow. The collar goes over the nipple and typically screws onto the neck of the bottle, forming a seal. Most, but not all baby bottles will also have a cap or travel cover that goes over the teat to keep it clean and to prevent small spills.<ref name="CDC 2018">Template:Cite news</ref> Some bottles may optionally have a disposable liner.<ref name="Kotowski"/>
Design concerns for the making of baby bottles often reflect safety or comfort. A safe baby bottle should not break, should not come apart easily into small or potentially harmful components, should not be made of materials that pose a health risk, and should be easy to clean so as to avoid bacterial contamination and illness.<ref name="Chicco">Template:Cite web</ref>
A bottle should also be comfortable for both caregiver and baby to use. Bottles that are lightweight and easy to hold can be desired by both babies and mothers. A variety of shapes are available. The design of containers, nipples or teats may mimic the shape of the mother's breast. Designers may try to mimic the flow rate of breastfeeding: the baby should be able to get enough nourishment, but at the same time not be overwhelmed or overfed.<ref name="Jenik">Template:Cite journal</ref><ref name="Marshall">Template:Cite journal</ref><ref name="Pados">Template:Cite journal</ref>
Materials
Over time a wide variety of materials have been used for infant feeding vessels (see History). The materials now most commonly used in baby bottle containers are glass and some types of plastics. Food-grade stainless steel and silicone rubber are also used. Each of these four materials—plastic, glass, silicone and stainless steel—has advantages and disadvantages.<ref name="Best"/> The standard materials used in teats/nipples are latex rubber and silicone.<ref name="Layton">Template:Cite web</ref>
A number of countries have regulations about allowable food contact materials. Ideally, the material making up the bottle should react as little as possible with the material in the bottle. No material is completely inert, but glass and stainless steel are relatively neutral materials which tend to remain stable and not interact with foods.<ref name=" Everts"/> The disadvantages of glass are that it tends to be heavy and can break more easily.<ref name="Mum">Template:Cite web</ref>
Plastics are lightweight and resistant to breaking.<ref name="Mum"/> Manufacturers find them easy to form into a variety of shapes.<ref>Template:Cite web</ref> A wide variety of plastics have been developed, some of which are not well understood in terms of reactivity. Some plastics have been found to be reactive with fluids such as breast milk and infant formula. Chemicals such as Bisphenol A (BPA) may "leach" from a bottle into the substance it holds. In addition, plastics may be more likely to break down when heated or cooled, for example, when being heated in a microwave or being boiled to sterilize them.<ref name="Pant">Template:Cite journal</ref><ref name="Work">Template:Cite web</ref>
Polycarbonate plastic was frequently used in baby bottles before 2011, and is still used in some countries.<ref name="Bashir">Template:Cite journal</ref> Polycarbonates contain Bisphenol A.<ref name="NYState">Template:Cite web</ref> Since 2008,<ref name=" Everts"/> at least 40 countries have banned the use of plastics containing Bisphenol A in baby bottles due to safety concerns (see Regulation).<ref name="Mahamuni"/> Bottles made of polycarbonate may be marked as "#7 PC".<ref name="Massachusetts">Template:Cite web</ref>
Bisphenol S (BPS) and Bisphenol F (BPF) have been used as substitutes for BPA. They are structurally similar. Comparisons of BPA, BPS and BPF have found that these chemicals have similar potency and action to BPA and may pose similar dangers in terms of endocrine-disrupting effects.<ref name="Rochester">Template:Cite journal</ref> This has led to criticisms of the chemical industry<ref name="Ben-Jonathan">Template:Cite journal</ref> and for calls to deal with bisphenols in groups, not individually. In 2021, the Canadian government agencies Environment and Climate Change Canada (ECCC) and Health Canada (HC) held consultations with the goal of grouping 343 known BPA analogs and functional alternatives.<ref>Template:Cite web</ref>
Polyethersulfone plastic (PES) does not contain BPA but does include Bisphenol S (BPS).<ref name="Singapore">Template:Cite web</ref> An assessment of a variety of different baby bottles in use in 2016, reported 4 bottles to be of "high concern", 14 bottles to be of "concern"; and only 6 bottles to be of "no concern" These of "no concern" included two polyamide (PA) and two polyethersulfone (PES) bottles, a stainless steel bottle, and one of the 17 polypropylene (PP) bottles tested.<ref name="Groh">Template:Cite web</ref>
Phthalates, found in polyvinyl chloride (PVC), are another area of concern.<ref name="LaMotte">Template:Cite news</ref> Referred to as "everywhere chemicals" because they are so common, phthalates make plastic more flexible, and have been used in pacifiers and nipples or teats for bottles.<ref name="phthalates"/><ref name="Handout">Template:Cite web</ref> Phthalates have been banned from use in feeding bottles in the EU.<ref name="Chuiyan">Template:Cite web</ref> In the USA, there have been repeated calls for the removal of phthalates by the U.S. Consumer Product Safety Commission (CPSC) and others.<ref name="CPSC">Template:Cite web</ref><ref name="CPSC2017">Template:Cite web</ref><ref name="LaMotte"/> Their use in children's toys and products was somewhat restricted by the Consumer Product Safety Improvement Act of 2008.<ref name="BCJ">Template:Cite web</ref><ref name="Lee">Template:Cite web</ref> Plastics labeled #3 may leach phthalates.<ref name="Lee"/> Latex rubber nipples may contain phthalates, so silicone nipples may be recommended instead. Packaging may indicate whether a product is "BPA-free" or "phthalate-free".<ref name="phthalates">Template:Cite web</ref>
Plastics may degrade over time in other ways, There are concerns that small beads of plastic may be released into fluids from some types of plastic bottles.<ref name="Kannan">Template:Cite journal</ref> In 2020 researchers reported that infant feeding bottles made out of polypropylene caused microplastics exposure to infants ranging from 14,600 to 4,550,000 particles per capita per day in 48 regions with contemporary preparation procedures. Microplastics release is higher with warmer liquids and similar with other polypropylene products such as lunchboxes.<ref>Template:Cite news</ref><ref>Template:Cite news</ref><ref>Template:Cite journal</ref> In 2022, the first study to examine the presence of plastic polymers in human blood found plastics of multiple types in the blood samples of 17 out of 22 healthy adults tested (nearly 80%).<ref>Template:Cite news</ref><ref name="Leslie">Template:Cite journal</ref> Medical experts have suggested reducing exposure to microplastics by not shaking plastic bottles or exposing them to high temperatures. Some recommend using alternative materials such as glass, silicone, or stainless steel.<ref>Template:Cite web</ref>
Baby bottle nipples (also called teats) are typically made from either silicone or latex rubber. When used for nipples, silicone is clear, durable, and slightly harder than latex. Natural rubber latex teats are elastic, tear resistant, and may feel softer. Latex can absorb odors, while silicone does not. Latex can break down if exposed to sunlight. Some people have allergies to latex.<ref name="Layton"/>
Size
Bottles tend to come in standard sizes, often Template:Convert and Template:Convert. Smaller bottles may be lighter and easier to hold and are often used with younger, smaller infants. There are concerns that larger bottles may lead to over-feeding, since parents are likely to encourage a baby to "finish" a bottle during a feeding.<ref name="Hua"/>
The height-to-width ratio of bottles is high (relative to adult cups) because it is needed to ensure the contents flood the teat when used at normal angles; otherwise the baby will drink air. However, if the bottle is too tall, it easily tips. There are asymmetric bottles that ensure the contents flood the teat if the bottle is held at a certain direction.Template:Citation needed
Shape
The shape of the bottle is related to both ease of use and ease of cleaning (see History). Designers sometimes suggest that naturalistic designs will mean that babies can transition between breast or bottle without issues.<ref name="Hua">Template:Cite web</ref><ref name="Jenik"/> Other bottles have been invented with unique shapes designed to speed up the warming and cooling of breast milk, saving time, reducing bacterial growth, and reducing exposure to temperatures that can damage the nutrients in breast milk.<ref name="Kavilanz">Template:Cite web</ref>
"Anti-colic" bottles have been put forward with the goal of reducing "gassiness" and distress when feeding. Designs often seek to minimize the sucking in of air by the baby while feeding. Some bottles try to minimize the mixing of air into the milk within the bottle. At the same time, it is desirable to avoid creating an internal vacuum as the infant sucks out fluids, since this will make it harder to feed. Designs may rely on the bottle's shape or incorporate different types of "venting".<ref name="Kotowski"/><ref name="Amereh">Template:Cite journal</ref><ref name="Jenik"/><ref name="Brown">Template:Cite journal</ref>
Some vented bottles, as well as bottles which use a collapsible liner collapses as the formula is drained, have been assessed favorably. They were reported to be comparable to a breastfeeding group in terms of milk intake, sucking patterns, and oxygenation.<ref name="Kotowski"/>
A 2012 study comparing two types of vented bottles with anti-vacuum features found no differences in infant growth between randomized groups. "Bottle A", a partial anti-vacuum design, was rated by parents as easier to assemble and clean. Infants fed using "Bottle A" were reported to engage in less "fussing", but no difference were found in "crying" or "colic" or in rates of ear infection.<ref name="Fewtrell">Template:Cite journal</ref> Health recommendations for the storage and handling of human milk typically focus on preventing the growth of dangerous bacteria, but some research is also being done on nutrition. Experimental studies have shown a degradation of retinol (Vitamin A) and α-Tocopherol (Vitamin E) content dependent upon the formation of bubbles in expressed breast milk and in formula. Seven models of bottles were studied, from six companies. Less degradation occurred when using a bottle feeding system designed to minimize the mixing of air with the bottle's contents.<ref name="Francis">Template:Cite journal</ref>
Teat flow rate
Teat characteristics can also have important implications for infant's sucking pattern and milk intake. Milk flow rate is defined as "the rate at which milk moves from the bottle nipple into the infant's mouth during bottle-feeding."<ref name="Park"/> Characteristics such as the shape of the nipple and the way it is perforated may impact flow rate and the coordination of sucking, swallowing and breathing during feeding.<ref name="Kotowski"/><ref name="Park"/>
Unfortunately, categorization and labeling of teats to indicate flow rate is neither standardized nor consistent. There is significant variability between and within brands and models.<ref name="Kotowski"/><ref name="Park">Template:Cite journal</ref> In one study, nipples labeled "Slow" or "Newborn" (0–3 months) had flow rates ranging from 1.68 mL/min to 15.12 mL/min."The name assigned to the nipple type does not provide clear information to parents attempting to choose a nipple".<ref name="Park"/> This may be of extra concern in the case of fragile infants.<ref name="Park"/> Specialized teats are available for infants with cleft palate.<ref name="Golisano">Template:Cite web</ref>
Variations and accessories
Bottles may be designed to attach directly to a breast pump for a complete "feeding system" that maximizes the reuse of the components. Such systems include a variety of drinking spouts for when the child is older. This converts the bottle into a sippy cup, a cup with lid and spout for toddlers, which is intermediate between a baby bottle and an open top cup. Bottles that are part of a feeding system may include handles that can be attached. The ring and teat may be replaced by a storage lid.<ref>Template:Cite web</ref>
Accessories for bottles include cleaning brushes, or bottle brushes, sterilizers, and drying racks. Brushes may be specially designed for a specific manufacturer's bottles and teats. Bottle sterilizers use different techniques for sterilization, including ultraviolet light, boiling water, and hot steam.
Bottle warmers warm previously made and refrigerated formula. Coolers designed to fit a specific manufacturer's bottles are available to keep refrigerated formula cold. Special formula powder containers are available to store pre-measured amounts of formula so that caregivers can pre-fill bottles with sterile water and mix in the powder easily. The containers are typically designed to stack together so that multiple pre-measured amounts of formula powder may be transported as a unit.Template:Citation needed
Institutions can purchase ready-to-feed formula in containers that can be used as baby bottles.<ref>Template:Cite web</ref> The lid screws off and is replaced by a disposable teat when the formula is ready to be used. This avoids storing the formula with the teat and possibly clogging the teat holes when formula is splashed within the bottle and dries.Template:Citation needed
Use
Cleaning and sterilization
Sterilization is a standard practice to prevent development of bacteria and resulting illness, that is more effective than sanitization. The Australian government and the United Kingdom's National Health Service guidelines recommend sterilization of baby bottles and other equipment either by using a cold water sterilizing solution such as by Milton sterilizing fluid, by steam sterilizing, or by boiling.<ref name="NHS">Template:Cite web</ref><ref>Template:Cite web Printed November 2008</ref><ref name="Australia"/><ref name="Philips">Template:Cite web</ref> It is important to clean and sterilize all parts of a bottle including containers, teats, and screw caps.<ref name="Australia">Template:Cite web</ref><ref name="RCN">Template:Cite web</ref> The United States Centers for Disease Control and Prevention, suggests that it may be sufficient to clean bottles with soap and water, in a dishwasher or by hand.<ref name="CDC">Template:Cite web</ref> This recommendation is based on the assumption that water supplies are clean and sanitation standards are high.<ref>Template:Cite web</ref><ref>Template:Cite news</ref><ref>Template:Cite web</ref> Some states, such as Illinois, continue to recommend sterilization in addition to washing.<ref name="IDHS">Template:Cite web</ref> Alberta, Canada recommends sterilizing bottles that are used with formula until an infant is at least 4 months old.<ref name="Alberta">Template:Cite web</ref>
However, there is evidence that bacteria such as E. coli can thrive in biofilms which form on the interior walls of the bottles. Gentle rinsing is not enough to prevent this. Even in developed areas, contamination continues to be a concern.<ref name="Rothstein" /><ref>Template:Cite journal</ref> In 2009 in the United Kingdom, researchers found contamination with Staphylococcus aureus in 4% of the baby bottles that parents reported were ready to fill after cleaning and disinfecting.<ref name="Byrd-Bredbenner">Template:Cite journal</ref><ref name="Redmond">Template:Cite journal</ref>
In lower-resource settings, risks of exposure to dangerous respiratory and enteric infections are higher.<ref name="Rothstein">Template:Cite journal</ref> A study of children admitted to hospital in Rawalpindi, Pakistan, found that 52.1% of the bottles their caregivers considered clean were actually contaminated. This occurred even though caregivers reportedly followed many of the recommended cleaning practices for cleaning and sterilizing bottles. The most common mistake was to boil the bottles for less than the minimum time recommended by WHO.<ref name="Ayaz">Template:Cite journal</ref><ref>Template:Cite web</ref>
Research into the preparation of infant formula in South Korea indicates significant levels of contamination can be transmitted through the handling of spoons and other utensils. Spoons, after being touched, were often left in the formula container, allowing bacteria to spread to the formula in the container. C. sakazakii, S. enterica, and S. aureus, all of which are potentially fatal, were able to surviving for weeks in contaminated infant formula.<ref name="Cho">Template:Cite journal</ref>
Understanding how recommendations are interpreted is important: in one study, leaving a bottle in water that had been previously boiled in a kettle was believed to be "boiling" the bottle. Researchers emphasize that health providers need to better educate caregivers; and that practical methods of bottle hygiene need to be suited to use in field settings. For example, in Peru, easy-to-adopt practices like using a bottle brush and detergent gave greater advantages than difficult-to-achieve procedures like boiling a bottle.<ref name="Rothstein"/> WHO (which strongly recommends breastfeeding) notes that in cases where bottle feeding is to occur, much better education is needed on how to use bottles.<ref name="UNICEF">Template:Cite web</ref>
Age-appropriate use
Nipples (teats) are typically subdivided by flow rate, with the slowest flow rate recommended for premature infants and infants with feeding difficulties. However, flow rates are not standardised and vary considerably between brands.<ref>Template:Cite web</ref><ref name="Park"/>
The NHS recommends a sippy cup or beaker be introduced by 6 months and the use of bottles discontinued by 1 year.<ref>Template:Cite web</ref> The AAP recommends that the cup be introduced by one year of age and that the use of the bottle by discontinued by 18 months.<ref>Template:Cite web</ref> The use of bottles is discouraged beyond two years of age by most health organisations as prolonged use can cause tooth decay.<ref>Template:Cite web</ref><ref name="Anil">Template:Cite journal</ref> Early childhood caries (ECC) is also a concern when considering how long breastfeeding should continue.<ref name="Lackey">Template:Cite journal</ref>
Regulation
While infant formula is highly regulated in many countries, baby bottles are not. Only the materials of the teat and bottle itself are specifically regulated in some countries (e.g. British Standards BS 7368:1990 "Specification for babies' elastomeric feeding bottle teats"<ref>Template:Cite web</ref>). In the USA, the Food and Drug Administration (FDA) regulates teats and the bottle materials.<ref name="Mo">Template:Cite web</ref><ref name="Consumer Watch">Template:Cite web</ref><ref name="FDA_Guidance">Template:Cite web</ref><ref name="FDA_Advice">Template:Cite web</ref>
In 1985 the FDA restricted allowable levels of nitrosamines (many of which are carcinogens) released from bottle teats.<ref>Template:Cite web</ref> Tests of bottle nipples available in the USA, Singapore, West Germany, England, Japan and Korea suggest that levels of nitrosamines in most rubber baby bottle teats are within recommended standards.<ref name="Weston">Template:Cite journal</ref><ref name="Se-Jong">Template:Cite journal</ref>
Another chemical that has been regulated is Bisphenol A (BPA), described as an endocrine disruptor in 1991.<ref name="Gore"/> Ongoing research into the possible effects of BPA at levels of exposure far below the U.S. government's BPA safety standards has led to concerns about the safety of plastics, including baby bottles. A 1999 Consumer Reports study showed that some polycarbonate baby bottles released unsafe amounts of BPA.<ref>Template:Cite web</ref><ref>Template:Cite news</ref> Concerns about BPA have been supported by further work.<ref name="Vogel">Template:Cite journal</ref><ref name="Halden">Template:Cite journal</ref><ref name="Rozek">Template:Cite journal</ref> (Research into the effects of BPA has frequently been hotly contested and controversial<ref name="Vandenberg">Template:Cite journal</ref> and issues have been raised over research biases due to industry funding and conflicts of interest due to close ties between government consultants and BPA manufacturers.<ref name="Vogel"/><ref name="Halden"/>) One result has been proposals to change the testing paradigm for assessment of endocrine-disrupting chemicals.<ref name="Vogel"/>
Research and public pressure have led to bans on the use of Bisphenol A in bottles and cups to be used by children.<ref name="Mo"/><ref name="SGS">Template:Cite web</ref> In 2008 Walmart announced that it would stop selling baby bottles and food containers containing BPA.<ref name="Gore">Template:Cite journal</ref> As of 2017, these were applied in at least 40 countries.<ref name="Mahamuni"/> Canada classified BPA as "toxic" in 2008 under the Canadian Environmental Protection Act.<ref name="Vogel"/> In 2011 use of bisphenol A in baby bottles was forbidden in all EU countries,<ref name="EU">Template:Cite web</ref><ref name=spiegel2015>Template:Cite news</ref> in China, in Malaysia, and South Africa.<ref name="Brazil">Template:Cite web</ref> In July 2012, the FDA stated that BPA would no longer used in baby bottles and sippy cups, in response to a petition from the American Chemistry Council stating that this was now in line with industry practice.<ref name="Tavernise">Template:Cite news</ref><ref name="DeNoon">Template:Cite web</ref> Other countries such as Argentina<ref name="Argentina">Template:Cite web</ref> and Brazil followed suit by prohibiting bisphenol A in baby bottles.<ref name="Brazil"/> Korea has extended its BPA ban to include all children's utensils, containers and packaging as of January 2020.<ref name="Korea">Template:Cite web</ref> There are calls for increased regulation of BPA in India.<ref name="Mahamuni">Template:Cite journal</ref><ref name="India">Template:Cite web</ref>
History
Throughout most of human history, infant nutrition has primarily depended on the availability of the child's mother or a wet nurse to breastfeed the infant.<ref name="Stevens"/> Beliefs and behaviors relating to infant feeding also vary widely across countries, cultures and times. Mothers and caregivers have also sought additional ways to feed children, sometimes referred to as "hand feeding".<ref name="Amy">Template:Cite book</ref><ref name="Fildes">Template:Cite book</ref> As early as Template:BCE, Egyptian pottery shows images of women breastfeeding their babies and also using animal horns to feed them.<ref name="Castilho"/>
Containers with hard spouts date to early in recorded time, as evidence by archeological finds (see image). The first vessels known to be used for feeding infants had an opening at one end for filling the bottle, and a second at the other to be put into the baby's mouth.<ref name="Greenberg"/><ref name="Wilke">Template:Cite journal</ref><ref name="Dunne">Template:Cite journal
- Template:Cite news</ref> Examination of the organic residues on ancient ceramic baby bottles shows that they were used as early as Template:BCE to feed babies with animal milk.<ref name="Wilke"/><ref name="Dunne"/>
Around Template:BCE to Template:BCE the Egyptians developed the ability to blow glass and the Romans blew clear feeding bottles of glass, but these did not obtain long-term popularity. Leather and wood were also used.<ref name="Greenberg"/><ref name="Peringer"/><ref name="WickesIV"/>
By the 1700s infant-feeding vessels such as the feeding-cups, bubby-pots, and sucking-pots were also being made<ref name="Castilho">Template:Cite book</ref><ref name="WickesIV"/> from materials that included pewter, tin, and silver.<ref name="Stevens"/>
In the 19th century, artificial feeding begin to replace wet nursing, and by 1900, wet nursing no longer existed as an organized profession.<ref name="Stevens"/> Changes to the feeding of infants were both socially and technologically driven. With industrialization, more mothers worked outside the home and could less easily breastfeed their children. Technological changes including the design of artificial feeding methods and the preparation of animal milks and other milk substitutes supported a transition to artificial feeding, but with mixed success. Understanding of both nutrition and sanitation lagged behind the introduction of artificial feeding methods, contributing to extremely high infant mortality rates in the Victorian era.<ref name="Castilho"/><ref name="Harris"/><ref name="Davenport">Template:Cite journal</ref><ref name="Romola">Template:Cite journal</ref><ref name="Fildes"/><ref name="Valerie">Template:Cite book</ref><ref name="Knodel">Template:Cite journal</ref>
In the United States, the first glass nursing bottle was patented by C.M. Windship in 1841. It was intentionally shaped like the mother's breast. In 1845 the Alexandra Feeder was marketed in England.<ref name="Greenberg"/><ref name="Diez">Template:Cite journal</ref> In Paris, the "Biberon" was introduced by M. Darbo: it was reported to be quite popular in a review from 1851.<ref name="Greenberg"/><ref name="Biberon">Template:Cite journal</ref> As the group American Collectors of Infant Feeders notes, by "the late 1800s a large variety of glass nursing bottles were produced in the United States", and the U.S. Patent Office had issued more than 200 patents for various designs of nursing bottles by the 1940s—designed to lie flat or stand up straight, with openings on their sides or ends, with detachable or permanently attached nipples, etc.<ref name="Bogucki">Template:Cite book</ref>
The design of baby bottles and particularly the ease of cleaning them had potentially serious consequences for the health of the children using them. Estimates of infant mortality suggest that 20-30% of infants died in the first year of life during the late Victorian era.<ref name="PBS">Template:Cite web</ref><ref name="Knodel"/><ref name="Davenport"/> During the 1890s, at a time when England's childhood mortality rates (ages 1-5) were declining, infant mortality rates actually rose.<ref name="Williams">Template:Cite journal</ref><ref name="Cambridge">Template:Cite web</ref> A bottle with a long Indian rubber tube ending in a teat remained popular until the 1920s because even very young babies could feed independently. The feeding tubes could be bought separately and were sometimes used with empty whiskey or medicine bottles. Almost impossible to keep clean, this type has been nicknamed the "murder bottle".<ref name="Harris">Template:Cite web</ref><ref name="Castilho"/>
Allen and Hanbury introduced a new bottle design with a removable valve and teat on the two ends in 1894, and an improved model, the Allenbury, in 1900. This "banana" bottle was easier to clean. Sometimes referred to as the "hygienic bottle", it helped to improve survival rates. Similar bottles were introduced by other manufacturers and remained popular from the 1900s to the 1950s.<ref name="Feeding"/> Eventually increased understanding of the causes and transmission of disease and improvements in medicine and public health began to reduce infant mortality.<ref name="Barrett">Template:Cite journal</ref><ref name="Preston">Template:Cite book</ref>
Heat-resistant Pyrex bottles were introduced to the American and British markets at different times. Pyrex bottles were first introduced in the United States by Corning Inc. in 1922. They were offered in three shapes (narrow neck, wide mouth, and flat) and multiple sizes, for a total of ten varieties. By 1925, the product line had been limited to a small subset of the original shapes and sizes.<ref name="CW">Template:Cite web</ref> In the 1950s a upright Pyrex bottle with a narrow neck was introduced. In the 1960s a wide-neck version was finally introduced to the UK market.<ref name="Feeding"/> The design of upright bottles with a wider mouth meant that they could be more easily cleaned, and sterilized in batches.<ref name="Click">Template:Cite web</ref>
Soft nipples of various materials were introduced early in the history of feeding (e.g., leather, cork, sponge, dried cow's teat filled with cloth). Many were very difficult to clean and when unsanitary could pose a serious threat to infant health.<ref name="Stevens">Template:Cite journal</ref><ref name="Greenberg">Template:Cite book</ref><ref name="Peringer">Template:Cite web</ref><ref name="WickesIV">Template:Cite journal</ref> Although Elijah Pratt of New York patented the first rubber nipple in 1845,<ref name="Greenberg"/> it took until the 20th century before materials and technology improved sufficiently to allow manufacture of a soft nipple that was practical for use. The invention of rubber (1840s) provided a material that was soft. Early black Indian rubber "had a very strong pungent smell", and did not survive repeated exposures to hot water. However, by the early 1900s more pleasing rubber nipples could be manufactured in volume and could withstand the heat of sterilization.<ref name="Feeding">Template:Cite web</ref><ref name="WickesIV"/>
During the 1940s nurse Adda M. Allen filed for multiple patents relating to the design of baby bottles,<ref name="Patents">Template:Cite web</ref> including the first disposable collapsible liner for a baby bottle.<ref name="Stokowski">Template:Cite web</ref> Her patent was one of many attempts to design a bottle to limit swallowing of air during feeding, and reduce gastric upset and spitting up. A plastic bottle with a disposable liner was eventually tested at George Washington University Hospital and marketed by Playtex.<ref name="Vance">Template:Cite web</ref>
Innovations such as the introduction of a working check valve in the nipple (to provide unidirectional flow of the liquid food) appeared as early as 1948 in a patent to J.W. Less.<ref>U.S. patent 2442656 A, "Nursing nipple for bottles", American J.W. Less in 1948 (www.google.ca/patents/US2442656, accessed February 27, 2014)</ref> This technology was picked up by others including Owens-Illinois Glass,<ref>U.S. patent 2747573 A, "Valved nursing nipple", issued to W.A. Schaich of Owens-Illinois in 1956 (www.google.ca/patents/US2747573, accessed February 27, 2014)</ref> eventually making its way into Gerber and all modern pressure-balancing bottle designs.<ref>E.g., see U.S. patent 6032810 A, "One-piece nipple/collar for nursers and the like", issued to the Americans M.A. Gilbertson, B. J. Meyers, E.A. Raleigh, and M.S. Stowe of Gerber Products Company in 2000 (www.google.ca/patents/US6032810), and U.S. patent 20120248056 A1, "Teat unit", issued to the Swiss R. Fischer, E. Furrer, and B. Emmenegger of Medela Holding Ag in 2012 (www.google.ca/patents/US20120248056). Accessed February 27, 2014.</ref> It is also used for adult drinking cups and various other products requiring fluid flow under vacuum.<ref>E.g., see U.S. patent US 7775394 B2, "Opening-force-maximizing device of an underpressure-activated valve for a drinking container", issued to the Norwegian K. Næsje of Smartseal As in 2010 (www.google.ca/patents/US7775394). Accessed February 27, 2014.</ref>
The modern business of producing bottles in the developed world is substantial. For 2018, the global baby bottle market was valued at 2.6 billion USD.<ref name="Global">Template:Cite book</ref> <ref name="Taylor">Template:Cite web</ref> In 1999 it was reported that the UK "feeding and sterilising equipment sector ... stands at £49m… [where] [s]ales of feeding bottles account for 39%" or £19.1m of that market.<ref>Template:Cite web</ref>
Controversy
The 2014 summary policy statement of the American Academy of Pediatrics (AAP) makes no specific mention of bottle feeding, but makes clear that "[b]reastfeeding and human milk are the normative standards for infant feeding and nutrition", and refers to decisions regarding the supply of infant nutrition as "a public health issue and not only a lifestyle choice… [g]iven the documented short- and long-term medical and neurodevelopmental advantages of breastfeeding".<ref>Template:Cite web</ref><ref name="pediatrics.aappublications.org">Template:Cite journal</ref> The AAP policy recommends breastfeeding exclusively for six months, continuing it with introduction of complementary foods, with an overall duration of "1 year or longer as mutually desired by mother and infant".<ref name="pediatrics.aappublications.org"/> The body of the policy statement notes and cites literature indicating that, in addition to the importance of mother's milk, the manner of the food delivery has implications: that "breastfed infants self-regulate intake volume", whereas bottle-fed infants receiving expressed breast milk or formula have "increased bottle emptying, poorer self-regulation, and excessive weight gain in late infancy", and that such early practice of self-regulation correlate with adult patterns of weight gain (ibid.).Template:Citation needed
The AAP policy notes that "[m]edical contraindications to breastfeeding are rare".<ref name="pediatrics.aappublications.org"/> The transmission of some viral diseases through breastfeeding is reportedly preventable, e.g., by expressing breast milk and subjecting it to Holder pasteurization.<ref name="pmid11847831">Template:Cite journalTemplate:Dead link</ref>
In response to public pressure felt from policies de-emphasizing bottle- and formula-feeding, efforts have arisen to support mothers experiencing physiologic or other difficulties in breastfeeding, and sites include individual views that attempt to weaken the scientific case of the AAP policy;<ref>Template:Cite web</ref> a book of the personal experiences and views of one mother committed to bottle/formula feeding, Bottled Up, by Suzanne Barston, has appeared.<ref>Template:Cite book</ref>
In 2007, a group of 38 researchers examined 700 studies into the use of the chemical compound Bisphenol A in plastics manufacturing, and warned that very low levels of exposure to the chemical can potentially pose adverse health effects, especially to a developing fetus.<ref>Template:Cite news</ref>Template:Update inline In 2024, multiple baby bottle companies, including Nuk, Tommee Tippee, and Dr. Brown's, were involved in a class action lawsuit for their bottles leaching microplastics when heated.<ref>Template:Cite news</ref>
See also
- Baby Friendly Hospital Initiative
- Breastfeeding promotion
- Breastfeeding contraindications
- Haberman Feeder
- Infant formula
- International Code of Marketing of Breast-milk Substitutes
- List of bottle types, brands and companies