Purpose: The purposes of this study were to characterize milk production, milk composition, and the lactational behavior of adolescent mothers, and to compare their lactational performance with that of adult females.
Methods: Twenty-two lactating mothers, 11 adolescents and 11 adults, were studied at 6-week intervals between 6 and 24 weeks postpartum. Milk production was determined by the test-weighing procedure. Milk nutrient composition was determined by standard chemical analyses. Frequency and duration of nursing and the use of supplemental formula and complementary foods were recorded.
Results: The amount of milk adolescents produced at 6, 12, 18, and 24 weeks postpartum ranged from 37-54% less (P < .05) than that of the adults and resulted in a 45% weaning rate at 18 weeks postpartum in the younger group. Milk nutrient concentrations were not significantly different between groups, with the exception of significantly higher sodium concentrations during early lactation in the adolescents' milk. Lactational behavior differed significantly between the adolescent and adult groups; however, with the exception of the lower frequency of daytime nursing and the tendency toward the early introduction of supplemental formula in the adolescent group, these behavioral differences were the result of the racial and ethnic differences between the two groups. The differences in lactational behavior did not contribute to the differences in milk production between the adolescents and adult mothers.
Conclusions: This preliminary study suggests that milk production was reduced in adolescent mothers compared with adult females. Although behavioral strategies that increase the frequency of daytime nursing and reduce the frequency of supplemental feedings may enhance the milk production of adolescent mothers, other biological factors may account for their poorer lactational performance.
PIP: In a comparative study of the lactational performance of 11 adolescent and 11 adult breast-feeding mothers from the US, adolescents were found to produce significantly less milk and lactate for a significantly shorter period of time than their adult counterparts. All subjects were assessed at 6-24 weeks postpartum. The adolescents produced 37% and 54% less milk at 6 and 24 weeks postpartum, respectively, than adult women. These differences in milk production were significant even when adjusted for differences in the frequency and duration of breast feeding episodes and use of supplementary feeds. The amount of dietary energy the infants of adolescents received from human milk alone was clearly inadequate, at every time point, to support normal growth rates. In both groups, the average frequency of nursing episodes during the first 12 weeks postpartum was 7 or more per 24 hours (consistent with current recommendations for adequate lactation); adolescents, however, spent significantly less time nursing and provided greater quantities of supplementary feeds. While all adult women breast-fed throughout the study period, 20% of adolescents had stopped breast feeding by 12 weeks, 50% weaned by 18 weeks, and 64% had discontinued breast feeding by 24 weeks. Unexpectedly, the energy, lactose, fat, total nitrogen, protein nitrogen, nonprotein nitrogen, sodium, potassium, calcium, and phosphorous concentrations showed little difference between the two age groups. The absence of data from the first 6 weeks of life makes it impossible to rule out a role for early formula supplementation in the decreased milk production of adolescents. It is believed,however, that adolescents may be biologically incapable of producing a full complement of milk because of their developmental immaturity.