Search

The study examines the effects of nursing practices on the duration of lactation in middle-class American women. Thirty-two nursing mothers were followed for 2 years post-partum, data being collected at eight home visits by interview and by nursing records kept by the mothers. Those women who nursed frequently (>8/day) during exclusive breastfeeding remained amenorrhoeic longer than infrequent nursers, introduced supplements later and did not resume menses as promptly thereafter. They continued an hour or more of night nursing during supplemented nursing. Duration of exclusive nursing and night nursing after supplementation were the major influences on duration of amenorrhoea. Mothers' age, weight-for-height, and nursing frequency before supplementation showed no significant effect but night nursing after supplementation was a major factor in post-supplementation duration of amenorrhoea. Those women who both supplemented later and maintained an hour of night nursing after supplementing remained amenorrhoeic for 6–10 months longer than those who supplemented early and/or reduced subsequent night nursing. [ABSTRACT FROM PUBLISHER]

Abstract. In industrialized societies, the unique pattern of crying in the first three months is "unexplained" but thought to be due to different biobehavioral factors from later crying behavior. To increase the range of the feeding and caretaking behaviors hypothesized to be relevant determinants of early crying? home observations and diary records were analyzed from samples of two subcultures of American middle-class women (La Leche League and "standard care" mothers; each n = 16) differing primarily in such practices. Both during and after the early crying stage, frequently fed infants cried or fretted less often (8.1 v 15.8 episodes per hour at 2 months of age; 10.7 v 16.6 episodes per hour at 4 months of age), and fewer of them exhibited rhythmic crying behavior (four v 11 at 2 months; eight v 13 at 4 months) during observations. However, only during the early crying period at 2 months were interval between feedings and maternal response latency shown to be independent determinants of cry/fret frequency (overall r[sup 2] = .35, P = .01), each factor accounting for approximately half of the explained individual variance. Furthermore, feeding interval was the only variable associated with rhythmic crying behavior at 2 months of age (r[sup 2] = .20; P = .01). In similar analyses at 4 months, there were no significant relationships with later crying or fretting. The results suggest that, in the presence of variation in feeding practice greater than that which is typical for our society, feeding interval may be a significant factor in early (but not later) crying behavior; furthermore, this effect is independent of and additive to the soothing effect of short response latency. Pediatrics 1988;81:529-536; cry, infant, feeding. [ABSTRACT FROM AUTHOR]

Abstract. Published norms for infant sleep/wake patterns during the first 2 years of life include an increase in length of maximum sleep bout from four to five to eight to ten hours by 4 months but little decrease in total sleep in 24 hours from 13 to 15 hours. Thirty-two breastfed infants were followed for 2 years and data collected on 24-hour patterns of nursing and sleep. Infants who were breast-fed into the second year did not develop sleep/wake patterns in conformance with the norms. Instead of having long unbroken night sleep, they continued to sleep in short bouts with frequent wakings. Their total sleep in 24 hours was less than that of weaned infants. This pattern was most pronounced in infants who both nursed and shared a bed with the mother, common practices in many nonwestern cultures. The sleep/wake development accepted as the physiologic norm may be attributable to the early weaning and separated sleeping practiced in western culture. As prolonged breast-feeding becomes more popular in our society, the norms of sleep/wake patterns in infancy will have to be revised. Pediatrics 1986;77:322-329; sleep/wake pattern, breast-feeding, infant. [ABSTRACT FROM AUTHOR]

Cebus monkey were less mature at birth than squirrel monkeys in terms of body wieght and brain weight in proportion to adult weight. Postnatally, cebus were slower to develop locomotion, perceptual-motor capacities, and object permanence. The differences in rate of development between the species increased with age. The findings indicate that the cebus have a longer period of infancy before becoming skilled at locomotion and manipulation. In view of the cebus monkey's recognized skill as a manipulator and problem solver, the long period of infancy suggests that cebus have evolved further in the direction of higher primates. [ABSTRACT FROM AUTHOR]