One of the Healthy People 2010 goals is to have 75 percent of mothers breastfeed their infant during the early postpartum period, with at least one half of mothers continuing to breast-feed until their child is at least six months of age. Although the rate of breastfeeding in the United States rose between 1990 and 2001, this goal has yet to be achieved. By 2001, the rate of exclusive breastfeeding at six months was 17.2 percent. The biggest increases in breastfeeding were observed in women with a high-school education or lower, who were black, and who were younger than 20 years; however, exclusive breastfeeding remains low in these groups. Various interventions, including education, counseling, and early problem-solving, have proven effective for increasing breastfeeding rates, whereas interventions that are not face-to-face or are too brief have not been effective. There is evidence that hands-on teaching, demand feeding, and postpartum support are essential components of successful interventions. However, few well-designed, randomized studies have compared a breastfeeding promotion intervention with usual care. Bonuck and colleagues conducted a randomized, nonblinded, controlled trial comparing intervention with usual care, focusing on patients with low incomes.

Authors of the Moms Into Learning about Kids (MILK) study randomized 382 prenatal care patients from two centers in the Bronx, N.Y., to receive a breastfeeding promotion intervention or usual care. Of these, 304 patients were eligible for postnatal follow-up. The breastfeeding promotion consisted of two prenatal meetings with a lactation consultant, as well as in-hospital and at-home postpartum meetings and telephone contact over 12 months. Baseline interviews were conducted to gather information about previous breastfeeding experience and breastfeeding knowledge, and follow-up telephone calls were made every month for the first four months postpartum, then every other month until one year. Mothers self-reported their breastfeeding behavior, which was then classified according to the ratio of breastfeeding to formula use, from level 1 (exclusive breastfeeding) to level 7 (exclusive formula feeding).

The majority of study participants already had children and had previous breastfeeding experience. Thirty percent intended to breastfeed exclusively, 49 percent planned to combine formula and breastfeeding, 9 percent planned to formula feed only, and 12 percent did not know. At two weeks postpartum, 90 percent of the intervention group and 65 percent of the control group were breastfeeding. Breastfeeding rates declined rapidly thereafter but stayed significantly higher in the intervention group up to week 20, except in week 18. There was a statistically significant difference through week 9 between patients in the intervention and control groups who breastfed 50 percent or more. Exclusive breastfeeding rates declined similarly in both groups. Additional analysis at weeks 13 and 52 showed that the risk of low breastfeeding rates was greater in the control group than in the intervention group, with an odds ratio of 1.90 at 13 weeks and 2.50 at 52 weeks. Participants born in the United States had a significantly lower rate of breastfeeding than foreign-born women. The intervention in this study had the greatest impact on this low breastfeeding group.

Overall, the patients in the control group had a 90 percent greater risk of low breast-feeding rates at three months and a 150 percent greater risk at 12 months. Women in the intervention group maintained a 50 percent rate of breastfeeding at six months compared with 33 percent in the control group. Women born in the United States had much lower breastfeeding intensity than foreign-born women. The authors suggest that prenatal visits and postpartum home visits were important contributors to the intervention's success. They acknowledge, however, that the intervention was laborintensive.