Sure, there have been campaigns before to promote breast-feeding -- this is the 13th World Breast-feeding Week -- but none as bold or unequivocal as this one. But does it need to be so provocative as to perhaps induce guilt in bottle-feeding moms, some of whom, after all, don't have a choice because of a baby's medical situation?

While the folks sponsoring the National Breast-feeding Awareness Campaign are diplomatic, they are not apologetic.

"We've tried to strike a balance between getting women's attention and providing information," says Christina Pearson of the Department of Health and Human Services. The ads are produced by HHS and the non-profit Ad Council and began to air last weekend in Greater Boston. You can also see them at www.adcouncil.org/campaigns/breastfeeding/.

The problem is that American women are too quick to supplement with formula because they have only vague ideas about the benefits of exclusive breast-feeding. "There's solid medical evidence [to support exclusive breast-feeding for six months], but the message just hasn't gotten out from the medical community," says Suzanne Haynes, HHS senior science advisor to the campaign. Here's what she wants parents to know:

It's healthier for the baby.

Breast-feeding for six months or more reduces the risk and significance of serial ear infections and gastrointestinal illness in babies, especially diarrhea, as well as the need for hospitalization for pneumonia, bronchitis, or asthma. "Breast milk kills bacteria, kills viruses -- it's like a miracle drug in that way -- and it passes on immunities. Formula doesn't do either. You get the best protection by not giving the baby anything else," Haynes says. Breast-fed babies also are less likely to develop childhood obesity, she says.

It's healthier for mom. Mothers who breast-feed for six months or more reduce their risk for breast cancer by 50 percent, says Anne Merewood, director of research at the Breast-feeding Center at Boston Medical Center.

It enhances the mother-baby bond. This has been downplayed over the years, because mothers who bottle-feed "don't want to hear it," says researcher Carol Melcher, clinical director of perinatal services at Loma Linda University Children's Hospital in California. During breast-feeding, a chemical is released in both bodies called oxytocin. "It's that warm, drowsy flush the nursing mother feels," Melcher says. "It creates a chemical connection between them." A bottle-feeding mom can connect well, too, she says, but she needs to be "taught to [hold the baby] close, create time for skin-to-skin touch, and make sure there is eye-to-eye contact."

While breast-feeding has steadily been rising in this country since 1971, when it hit an all-time low (only 5.4 percent of mothers nursing at 6 months, even with supplementation), the numbers aren't near what they should be, says Mary Lofton, a spokeswoman for La Leche League International, a nonproft that supports women who want to breast-feed. The goal for the HHS campaign is to have 50 percent of all women breast-feed exclusively for six months by 2010.

That's ambitious. In 2002, the most recent year for which statistics are available, 70 percent of American women nursed in the hospital but only 46 percent did so exclusively. At the six-month mark, about 17 percent of women are nursing exclusively, according to a survey by Abbott Laboratories. The numbers are even lower for African-American women: In 2002, 27.5 percent breast-fed exclusively in the hospital. Six months later, 9.5 percent of black mothers were breast-feeding exclusively. Lofton says the numbers are so low for black women because their grandmothers and mothers embraced bottle-feeding as a symbol of upward mobility.

Christy Egun of Hyde Park, a first-time African-American mother, is bucking that trend.

Although she's pretty sure her mother and grandmother did not breast-feed, she's nursing 12-week-old Grayson exclusively and hopes to continue for a year. "It's been difficult," she concedes. "I had a C-section. But I want to give him all the pieces he needs to be successful as an infant in the world." A marketing executive, she plans to pump when she goes back to work later this month.

Going back to work is one of three times when women tend to abandon breast-feeding. Stefanie Smith of Waltham, for instance, nursed Jessica, now 9 1/2 months, for eight weeks. "My goal was to do it for longer, but I take public transportation and I didn't want to bring the milk back and forth on the bus," she says.

Melcher says other mothers typically stop because there's no place at work to express other than the restroom, or because their breaks aren't long enough. Expressing typically takes 10 to 20 minutes. For mothers on the verge of making the decision to stop, she offers this incentive:

"When the baby enters day care, that's when it's important to breast-feed even more," she says. "If the mother breathes the germs the baby is exposed to for 20 minutes a day -- she just sits in the day care room -- her body will make specific antibodies against the germs the baby is exposed to."

Ironically, another common stopping point for women is while they are in the hospital.

In her study, Melcher found that about half the mothers at 20 hospitals in California who went into labor expecting to breast-feed exclusively left the hospital having supplemented with formula. For 10 percent of them, it couldn't be avoided: there were medical reasons, often from a premature birth. More likely, she says, it happens because a well-intentioned nurse says, "'You're exhausted. Let me take the baby while you rest."

That so-called kindness ends up contributing to a mother's thinking she doesn't have enough milk, the No. 1 reason women stop nursing, says Rachel Colchamiro, breast-feeding coordinator for the Mass. Department of Public Health. Breast-feeding is a supply-and-demand process. "If the baby is hungry and fed formula, the mother loses an opportunity to put the demand on her body to produce more milk," she says.

Amy Newbery, a registered nurse and lactation consultant on staff at Boston Medical Center and Isis Maternity in Brookline, says women often get caught in a cycle of thinking their newborn is hungry because he cries so much and wants to suckle all the time and because their early milk doesn't look like milk.

"In the first three days, what you've got is colostrum. It's the ultimate first vaccination, the purest milk for babies," she says. It's very thin looking, however, not the flowing milk that happens at about day three or four. The combination of the 24/7 suckling, the crying, and the colostrum leads women to think their "milk isn't in," that the baby is hungry and they need to supplement.

That describes Katie Dinardo of Pembroke.

"I swear he starved," she says of her first-born, Bryan, now 7. "I nursed for 3 1/2 days. I was on the point of hysteria. I called my mother, crying. She said, `Just give him a bottle, see what he does.' He ate 5 ounces, slept six hours. That made my decision for me," she says.

Newbery is sympathetic. "I see lots of aunties and grandmas who didn't nurse and who say, `That baby's starving! Give her a bottle!" That, as well as pain that typically comes from incorrect positioning, are the two reasons women who are nursing exclusively when they leave the hospital don't make it past the two-week mark. She urges moms to get the personal and professional support they need, including from the pediatrician.

"When you interview your pediatrician [prenatally], be sure there will be respect for you as a breast-feeding mom," she says.

With her second, Jason, now 12 months, Katie Dinardo went straight to formula.

"I wasn't about to put my family through that a second time," she says, adding that she was under the misimpression that you had to nurse for a year to give your baby the benefits. She might well be a mother who would have benefitted from the Breast-feeding Awareness campaign.By the way, if you feel squeamish when you see either the "Mechanical Bull" ad or a similar one called "Log rolling," be reassured: The actresses are wearing fake bellies.

Contact Barbara Meltz at meltz@globe.com.