1. A healthier baby "The incidences of pneumonia, colds and viruses are reduced among breastfed babies," says infant-nutrition expert Ruth A. Lawrence, M.D., a professor of pediatrics and OB-GYN at the University of Rochester School of Medicine and Dentistry in Rochester, N.Y., and the author of Breastfeeding: A Guide for the Medical Profession (Elsevier-Mosby). Gastrointestinal infections like diarrhea—which can be devastating, especially in developing countries—are also less common.
2. Long-term protection, too Breastfeed your baby and you reduce his risk of developing chronic conditions, such as type I diabetes, celiac disease and Crohn's disease.
3. Stronger bones According to Lawrence, women who breastfeed have a lower risk of postmenopausal osteoporosis. "When a woman is pregnant and lactating, her body absorbs calcium much more efficiently," she explains. "So while some bones, particularly those in the spine and hips, may be a bit less dense at weaning, six months later, they are more dense than before pregnancy."
4. Lower SIDS risk Breastfeeding lowers your baby's risk of sudden infant death syndrome by about half.
5. Fewer problems with weight It's more likely that neither of you will become obese if you breastfeed him.
6. A calorie incinerator You may have heard that nursing burns up to 500 calories a day. And that's almost right. "Breast milk contains 20 calories per ounce," Lawrence explains. "If you feed your baby 20 ounces a day, that's 400 calories you've swept out of your body."
7. It's good for the earth Dairy cows, which are raised in part to make infant formula, are a significant contributor to global warming: Their belching, manure and flatulence (really!) spew enormous amounts of methane, a harmful greenhouse gas, into the atmosphere.
8. Better healing postdelivery The oxytocin released when your baby nurses helps your uterus contract, reducing postdelivery blood loss. Plus, breastfeeding will help your uterus return to its normal size more quickly—at about six weeks postpartum, compared with 10 weeks if you don't breastfeed.
9. Less risk of cancer Breastfeeding can decrease your baby's risk of some childhood cancers. And you'll have a lower risk of premenopausal breast cancer and ovarian cancer, an often deadly disease that's on the rise.
10. An unmatched feeling of power "It's empowering as a new mother to see your baby grow and thrive on your breast milk alone," Lawrence says.
11. A custom-made supply Formula isn't able to change its constitution, but your breast milk morphs to meet your baby's changing needs. Colostrum—the "premilk" that comes in after you deliver—is chock-full of antibodies to protect your newborn baby. "It's also higher in protein and lower in sugar than 'full' milk, so even a small amount can hold off your baby's hunger," says Heather Kelly, an international board-certified lactation consultant in New York City and a member of the Bravado Breastfeeding Information Council's advisory board.
When your full milk comes in (usually three to four days after delivery), it is higher in both sugar and volume than colostrum—again, just what your baby requires. "He needs a lot of calories and frequent feedings to fuel his rapid growth," Kelly explains. "Your mature milk is designed to be digested quickly so he'll eat often."
12. More effective vaccines Research shows that breastfed babies have a better antibody response to vaccines than formula-fed babies.
13. A menstruation vacation Breastfeeding your baby around the clock—no bottles or formula— will delay ovulation, which means delayed menstruation. "Breastfeeding causes the release of prolactin, which keeps estrogen and progesterone at bay so ovulation isn't triggered," Kelly explains.
"When your prolactin levels drop, those two hormones can kick back in, which means ovulation—and, hence, menstruation—occurs."
Even if you do breastfeed exclusively, your prolactin levels will eventually drop over the course of several months. Many moms who solely nurse will see their periods return between six and eight months after delivery, Kelly adds; others don't for a full year.
14. Less time off work Your baby will be ill less often, so that means fewer sick days for you.
15. It's cheap! According to La Leche League International, the cost of formula can range anywhere from $134 to $491 per month. That's $1,608 to $5,892 in one year!
16. A great way to learn about your baby "You have to read your baby's 'satiety cues' a little better, because unlike with a bottle, you can't see how much he's eaten," Kelly says. "You have to rely on your own instincts and your baby's behavior to know when your baby is full."
17. You can stash the condoms—for now Breastfeeding can be 98 percent to 99 percent effective as a post-baby birth control option if a few guidelines are followed: Your period must not have resumed; you must breastfeed at least every four hours around the clock; you must not give your baby any pacifiers, bottles or formula; and you must be less than six months postpartum.
According to Kelly, nighttime feedings are the most important to the "lactation amenorrhea method," so do not let your baby (or yourself ) sleep through a feeding. "Going long stretches at night without nursing seems to be directly responsible for the return of ovulation," she says. Prematurely sleep training your baby can also hasten ovulation.
18. There's nothing easier Simply pull up your shirt and nurse. Breast milk is always available and always at the right temperature.
19. Benefits for all According to a study published in the journal Pediatrics, the United States would save about $13 billion per year in medical costs if 90 percent of U.S. families breastfed their newborns for at least six months.
20. Better friendships "Breastfeeding helps cultivate relationships with other moms," Kelly says. Whether it's talking about parenting styles, nighttime feedings or engorgement, nursing allows women to forge positive postpartum relationships. Adds Kelly, "Women are supposed to be sitting together, nursing and taking care of babies."