eFor the category of partially breast-fed infants 0–3.9 mo, the committee estimated that the number of infants aged 0–0.9 mo was 25% of the category total and the number of infants aged 1–3.9 mo was 75% of the total. In the absence of data on the proportion of infants to anticipate in each of the first 4 mo after birth, the committee assumed the distribution would be approximately equal in each month, using the census data for children under the age of 5 y as a model (20.0% ± 0.3%, mean ± SD) (U.S. Census Bureau, 2004).
fOne alternative is to provide one small can (up to 15 oz) of powdered formula to breastfed infants during the first mo postpartum if requested by the mother. The committee used the assumption that the number of breastfeeding mothers requesting formula in the first mo would approximate 50% of the current number of partially breastfeeding mother/infants pairs. The additional monthly cost per participant who choose this option would be $9.30 in pre-rebate costs and $2.98 in post-rebate costs. Using the estimate of 50% of the current partially breastfeeding participants (0.5 × 129,949 = 64,747) for the first mo postpartum, the additional monthly program cost would be $193,626 or an additional 2.4¢ in the average cost per participant.
gNumber of participants was calculated using data Exhibit 3.1 from USDA’s WIC Participant and Program Characteristics, 2002 (Bartlett et al., 2003), recognizing that some discrepancies exist in these data. An infant is defined as a participant who, at certification, is under 1 y of age and who would be classified as a child at the age of 366 d. However, in 2002, about 2.84% of WIC participants categorized as 1-y-old children are, in fact, 11-mo-old infants who have been recertified as 1-y-old children; additionally, about 0.38% of WIC participants who are classified as infants are participants who are older than 366 days.
hPercentage of infants fully or partially breast-fed at 4–5.9 mo of age was extrapolated from data for infants at 3 and 6 mo of age (CDC, 2004b; Abbott Labs, 2002, 2003 [2001 data]).
iPercentages of infants fully or partially breast-fed at 6–11.9 mo of age were calculated as the average of data reported for infants at 6 mo (CDC, 2004b, 2004c) and 12 mo of age (CDC, 2004b, 2004c; Briefel et al., 2004a).
jThe committee calculated the number of participants in each category using data from the USDA sponsored WIC Participant and Program Characteristics 2002 (Bartlett et al., 2003); data from Exhibit 3.1 (Bartlett et al., 2003) were used to estimate the number of participants ages 1–1.9 y and 2–4.9 y.
kPercentage distribution of women as fully breastfeeding (55% of the total) or partially breastfeeding (45% of the total) was calculated according to the distribution of infants identified as fully or partially breast-fed (see notes h and i).
DATA SOURCES: Price data are from Economic Research Service, USDA (ERS, 2004b, 1999 price data; Oliveira et al., 2001, 2000 infant formula price data); ACNielsen Homescan (ACNielsen, 2001, price data for 2001obtained through ERS, USDA); and the Bureau of Labor Statistics, U.S. Department of Labor (BLS, 2004a, 2002 price data). Data on rates of participation are from resources published by USDA (Bartlett et al., 2003, 2002 data; Kresge, 2003, 2002 data). Data on percentages of infants breast-fed were obtained from the 2003 National Immunization Survey (CDC, 2004b, 2004c) and published resources (Abbott Labs, 2002, 2003; Briefel et al, 2004a).