The median breastfeeding frequency in the solids and formula groups, from 8 weeks before the start of solids or regular formula feeds to 14 weeks after the start. The 14-day period when solids and regular formula feeds were started is set to zero. • indicates the solids group; ○, formula group.
The median breastfeeding frequency by age at introduction of solids in the solids group and of formula in the formula group, from 8 weeks before the start of solids or regular formula feeds to 14 weeks after the start. The 14-day period when solids or formula was started is set to zero. Solids: ▪ = <4 months; ▴ = 4 to 6 months; × = ≥6 months. Formula: □ = <4 months; ▵ = ≥4 months (includes 3 infants starting with regular formula at 6 months).
Individual changes (%) in breastfeeding frequency. The breastfeeding frequency 2 weeks before the start of solids or regular formula feeds is compared with the frequencies 2, 4, and 8 weeks after the start in the individual infant. The box-plots show the median values, 25th and 75th percentiles, and outliers (○) in the solids and formula groups.
Cox regression analysis of breastfeeding duration by feeding regime, adjusted for birth year and maternal education. □ = infants starting with >1 formula feed/day at <4 months of age (n = 63); ▿ = at 4 to 6 months of age (n = 63); ○ = or at 6 months or later (n = 57); + = infants given formula only occasionally (n = 47); and • = infants given only solids, never formula (n = 47).