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Quick Reference and Fact Sheets

March of Dimes Professionals and Researchers


Breastmilk is the best food for most babies. Breastmilk contains all the nutrients a baby needs for healthy growth and development during the first six months of life, as well as substances that help protect a baby from many illnesses. Breastfeeding provides health benefits for the mother, including earlier return to her pre-pregnancy weight. And there are emotional benefits for mother and baby from the special bond that develops between them. The March of Dimes urges all new mothers to breastfeed if they are able. The American Academy of Pediatrics (AAP) recommends that a baby be breastfed for at least twelve months¹. However, even babies who breastfeed for only a short period of time experience health benefits.

What are the benefits of breastfeeding for the baby?

Breastmilk provides the ideal amounts of protein, sugar, fat and most vitamins a baby needs for healthy growth and development. Breastmilk also contains substances called antibodies that help protect a baby from many illnesses. Studies show that breastfed babies are less likely than formulafed babies to have ear infections, lower respiratory infections (such as pneumonia and bronchiolitis), meningitis, urinary tract infections and diarrhea¹. Studies also suggest that breastfed babies may be less likely to die from sudden infant death syndrome (SIDS)¹. Breastmilk is easy for a baby to digest, so the baby may have less gas and discomfort than a formula-fed baby.

The health benefits of breastfeeding can last a lifetime. Studies suggest that children and adults who were breastfed are less likely to develop asthma, insulin-dependent diabetes and certain cancers (leukemia, lymphoma and Hodgkin's disease)¹. Babies who were breastfed may be less likely to become obese later in life¹.

Breastfeeding also may enhance brain development. Some studies suggest that children who were breastfed may score higher on tests of cognitive ability than children who were fed formula¹.

What are the benefits of breastfeeding for the mother?

Breastfeeding leads to increased levels of a hormone called oxytocin that causes the new mother's uterus to contract. This contraction helps reduce bleeding after delivery and shrink the uterus to its pre-pregnancy size. Breastfeeding also delays the return of a woman's menstrual period, helping her to postpone another pregnancy. It is difficult to determine when fertility will return in a breastfeeding mother. So if a woman and her partner do not want another baby right away, they should use birth control when they start having sex again.

Breastfeeding mothers burn more calories than women who don't breastfeed, so they tend to return to their pre-pregnancy weight more quickly. This is true even though a breastfeeding woman should eat 500 extra calories a day to keep up her milk supply and meet her own nutritional needs². Studies suggest that breastfeeding may help reduce a woman's risk of breast and ovarian cancer1,2.

How do breastmilk and formula differ?

Breastmilk contains all the ingredients that a human baby needs to thrive. Formulas based on cow's milk or soy include many of the same nutrients, but not all. Formula makers cannot duplicate all of the ingredients in breastmilk, because some of the ingredients are not known.

Breastmilk includes antibodies and other immunesystem substances that help protect a baby from illness. It contains growth factors, hormones and other substances that help a baby grow and develop at an appropriate rate. Breastmilk also contains fatty acids that appear to promote brain development and possibly increase intelligence. Some formula makers add two of these fatty acids – DHA (docosahexaenoic acid) and ARA (arachidonic acid) to their products. However, the long-term benefits of formula enhanced with these fatty acids are not known.

The AAP recommends that all babies, including those who are exclusively breastfed, consume at least 200 international units (IU) of vitamin D to help prevent a bone-weakening disease called rickets¹. Exclusively breastfed babies are at increased risk of rickets because breastmilk is low in vitamin D. Most formula-fed babies get enough vitamin D. Breastfed babies should receive multivitamin drops containing vitamin D starting in the first two months of life¹.

Unlike formula, breastmilk changes as a baby develops and provides just the right amount of nutrients and other substances that a baby needs at various stages of development. For example, for the first few days after delivery, a woman's breasts produce a think, yellowish form of milk called colostrum. Colostrum is high in proteins and immune substances that the baby needs in the early days of life. After this time, the mother begins to produce greater quantities of a thinner form of milk that is lower in protein and higher in fat. The breastmilk of a mother of a premature baby is different from that of a mother of a full-term baby and is designed to meet her baby's needs at his/her specific stage of development.

How long should a woman breastfeed her baby?

The AAP recommends that infants be fed only breastmilk (no water, formula, other liquids or solids) for about the first six months of life¹. Women should continue to breastfeed their babies for the next six months while solid foods are introduced. They can continue breastfeeding after 12 months as long as the mother and baby desire.

However, a new mother should keep in mind that breastfeeding for even a short period of time provides health benefits for her baby.

Who should not breastfeed their baby?

Breastfeeding is recommended for the vast majority of mothers and babies. However, there are a few exceptions. Women in the United States who have HIV (human immunodeficiency virus, the virus that causes AIDS) should not breastfeed because they can pass the virus on to their babies in their breastmilk1,2.

This recommendation may differ in some developing countries. Women who have active tuberculosis and who have not been treated with medications should not breastfeed. A woman with an illness, such as the flu, usually does not need to interrupt breastfeeding because she will pass along antibodies to her baby that will help protect him/her from the illness.

Women who have had breast surgery, such as breast enlargement or reduction, should discuss breastfeeding with their healthcare providers. Most will be able to breastfeed, though some may have problems, such as not being able to produce enough milk.

Most women who take medications for chronic health conditions (such as high blood pressure or asthma) or antibiotics for common illnesses (such as strep throat) can safely breastfeed. While small amounts of many medications do enter breastmilk, most do not harm the baby. However, a woman should always check with her healthcare provider and her baby's provider before taking a medication (including over-the-counter and herbal preparations) to see if it is safe to take while breastfeeding. The healthcare provider may switch a woman to a safer medication. Or the provider may advise her to take her medication soon after breastfeeding, so most of the medication will be out of her system before the next feeding.

A small number of medications are believed to pose a risk to a breastfeeding baby. A woman who takes these medications will probably need to stop breastfeeding temporarily and formula-feed her baby as long as she takes the medication. These drugs include cancer drugs, radioactive compounds (used with certain imaging tests) and some drugs used to treat migraine headaches1,2. Illicit drugs, such as cocaine and amphetamines, also pose a risk to breastfeeding babies, as do large amounts of alcohol¹. Women should avoid these substances while breastfeeding.

Women who are vegetarians can breastfeed their babies, but they should discuss their diets with their healthcare provider. According to the Centers of Disease Control and Prevention (CDC), some vegetarians may need to take a vitamin supplement containing vitamin B12³. Without supplementation, breastfed babies of women who eat no animal products may not get enough vitamin B12, which may cause brain abnormalities.

Women whose babies have galactosemia, an uncommon genetic disorder of body chemistry, should not breastfeed¹. Babies with galactosemia cannot process the sugar in milk (including breastmilk and dairy-based formulas) and may die or develop mental retardation if they eat any milk products. Babies with galactosemia must be fed a non-dairy formula. Newborn screening tests detect most babies with galactosemia soon after birth.

Do premature or sick babies benefit from breastfeeding?

Many premature or sick babies cannot feed from the breast right away. However, the benefits of breastmilk, including protection from many diseases, may be especially crucial for these babies.

Mothers can use the breast pump to express their milk so that the milk can be fed to their babies through a tube or with a dropper. By pumping her breasts, a mother keeps up her milk supply so that her baby can breastfeed when she is stronger.

How many women breastfeed their babies?

In 2003, about 70 percent of women in the United States were breastfeeding their babies when they left the hospital4. About 36 percent of women were still breastfeeding their babies at six months of age4. These are the highest numbers ever recorded in the United States.

Where can a woman find information and assistance with breastfeeding?

Pregnant women and their partners should consider taking a breastfeeding class. Many hospitals offer these classes. After delivery, the postpartum nurse and the baby's healthcare provider will help assure that breastfeeding is going smoothly before the woman leaves the hospital. Breastfeeding should not hurt when done correctly. Many hospitals also have a lactation consultant on staff to provide assistance. Once home, a mother should discuss breastfeeding questions with her baby's health careprovider or a lactation consultant. Very few women cannot produce enough milk for their babies, so breastfeeding moms should ask for assistance when they need it.

All breastfed babies should be checked by a healthcare provider at three to five days of age¹. The provider will examine the baby and check to see if he/she has jaundice (yellowing of the skin, which occasionally requires treatment). The provider also will weigh the baby to make sure he is gaining enough weight.

The following organizations can also provide materials and assistance:

American Academy of Pediatrics (847) 434-4000
La Leche League, International (800) 525-3243
International Lactation Consultant Association (919) 861-5577
American College of Nurse-Midwives
Online Community of Mothers and Nursing Professionals


1. American Academy of Pediatrics (AAP). "Breastfeeding and the Use of Human Milk: Policy Statement." Pediatrics, volume 115, number 2, February 2005, pages 496-506.

2. American College of Obstetricians and Gynecologists (ACOG). "Your Pregnancy and Birth," 4th Edition. ACOG, Washing, DC, 2005.

3. Centers for Disease Control and Prevention (CDC). "Neurologic Impairment in Children Associated with Maternal Dietary Deficiency of Cobalamin" – Georgia, 2001. Morbidity andMortality Weekly Report, volume 52, number 4, January 31, 2003, pages 61-64.

4. Centers for Disease Control and Prevention (CDC). "Breastfeeding Practices: Results from the 2003 National Immunization Survey." Update 8/11/04.

Additional Reference

Meek, J.Y. (editor-in-chief). American Academy of Pediatrics New Mother's Guide to Breastfeeding. New York: Bantam Books, 2002. August 2005.

Copyright 2008 March of Dimes Foundation. All rights reserved. The March of Dimes is a not-for-profit organization recognized as tax-exempt under Internal Revenue Code section 501(c)(3). Our mission is to improve the health of babies by preventing birth defects, premature birth, and infant mortality.

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