baby bottle is a bottle with
a teat (also called a nipple in the US) to drink directly from.
It is typically used
when a mother does not breastfeed, or if someone can not (as
conveniently) drink from a cup, for feeding oneself or being
In particular it is used to feed an infant
with infant formula
or pediatric electrolyte
Dimensions and design
A large-sized bottle typically holds 270 ml; the small size 150 ml.
It is composed of a bottle itself, a teat, a ring to seal the teat
to the bottle, a cap to cover the teat and optionally a disposable
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.
Teats (or nipples)
The teat itself is typically slimmer and more flexible than the
mother's nipple. Contents of a bottle can flow more quickly than
. Specialized teats that
attempt to mimic the shape of the breast exist to help babies to
switch back and forth between bottle feeding and breast feeding for
cases where "teat confusion" occurs. Teats come in a selection of
flow rates. Different flow rate teats either have more holes or
larger holes. The correct flow rate needs to selected based on the
age of the infant. Variable flow rate teats are available for older
infants. The hole is asymmetric so that by turning the bottle/teat,
different flows can occur. Specialized teats are available for
infants with cleft palate
"Vented" bottles allow air to enter the bottle while the baby is
drinking without the need to break the baby's suction during
feeding. Alternatively a bottle liner can be used to enclose the
formula instead of directly in the bottle. The liner collapses as
the formula is drained.
Vented bottles work by allowing air to enter while preventing the
liquid inside from escaping. Avent
is the most
popular brand in this category. It works by an "anti-vacuum skirt"
in the base of the teat, where it forms a seal with the bottle. The
skirt acts as a one way valve, allowing air to enter the bottle but
not liquids to leave. If the sealing ring is tightened too much,
the skirt is compressed too tightly to allow it to open and the
bottle will not vent. If the sealing ring is too loose, liquid
leaks from the bottle.
There are multiple patents for technologies in this area. Initial
designs called for a complex spring and valve system that was
impossible to clean and sterilize. Current research is in
specialized materials with microscopic pores
that allow the entry of air without the escape of liquids. This
avoids the caregiver having to get the sealing ring tension just
right. It remains to be seen whether these materials can withstand
the rigours of daily cleaning and sterilization. Another
competitor, Dr. Brown's, offers a system whereby the vented air is
conducted through a tube to the bottom of the bottle where the
airspace is when the bottle is in use. This avoids the vented air
from bubbling through the liquid and unnecessarily aerating the
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
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.
Accessories for bottles include cleaning brushes and drying racks.
Brushes may be specially designed for a specific manufacturer's
bottles and teats. Bottle warmers warm previously made and
refrigerated formula. Cooler 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.
Specialty, "designer" bottles are now quite common as novelty gifts
for parents or just something interesting for the child. They
either have special logos or are of special shapes (e.g., animals).
Some even have a hole in the middle. Depending on the shape, these
bottles can be quite difficult to clean. Another specialty bottle
is made from heat sensitive materials that act as a built-in
thermometer. If the contents are too hot, the bottle changes
Institutions can purchase ready-to-feed formula in containers that
can be used as baby bottles. 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.
If necessary, bottles can be sterilized by boiling in hot water, in
a specialized bottle sterilization appliance (which typically uses
steam) or in a specialized sterilization container that is
microwaved. Modern bottles are difficult to sterilize in boiling
water because they tend to float. Bottles were originally composed
of glass which was dangerous when babies learned to feed themselves
and held the bottle. Mainly for cost reasons, modern bottles are
. Since bottles have to
be made to withstand the heat of sterilization, the bottle can also
withstand the heat of dishwashers and are dishwasher-safe.
There is some concern about BPA leakage on polycarbonate bottles
due to extended dishwasher or boiling. While bottles were
traditionally sterilized in the past, unless there are infant
health concerns, or concerns about water contamination, the current
recommendation is that baby bottle sterilization can be replaced by
cleaning with hot soapy water..
While infant formula is highly regulated, 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"
). In the USA, the Food and Drug Administration
(FDA) also regulates teats
and the bottle materials. In 1985 it tightened
allowable levels of nitrosamines
released from bottle teats
. A 1999 Consumer Reports
study suggesting that
plastic bottles release unsafe amounts of bisphenol A
was denounced as sensationalism
because of the unreasonable conditions the bottles were subject
. Findings since, however, have renewed the
initial concerns (see Bisphenol A - Possible
).   
More research is needed.
Bottles with hard spouts go back to prehistory
first consisted of urns with two openings: one for pouring the
liquid into the bottle and the other to be put in the baby's mouth.
Soft teats of various materials were tried but were very difficult
to clean. The invention of vulcanized rubber
provided a material that was soft and could withstand the heat of
sterilization. Elijah Pratt of New York patented the first rubber
teat in 1845 
. It took until the 1900s before the
technology was perfected for a practical soft teat such that the
baby bottle could become a practical and safe alternative to
In the UK in 1999, "the feeding and sterilising equipment sector
... stands at £49m. Sales of feeding bottles account for 39% of the
, or £19.1m.
Breastfeeding experts and the American Academy of Pediatrics
contend that feeding anything (even breast milk) to a child with a
bottle can interfere with successful establishment of breastfeeding
in the first two months.The transmission of some viral diseases
through breastfeeding can be
prevented by expressing breast milk and subjecting it to Holder
Baby bottles are discouraged by the World Health Organization
considers drinking from a cup safer.
- Should You Sterilize Your Baby's Bottles?
- Glass Baby Bottles using Silicone Encapsulated Sleeve to
prevent broken glass accidents.