Effects of age at introduction of complementary foods to breast-fed infants on duration of lactational amenorrhea in Honduran women.

Lactational amenorrhea (LA) is associated with postpartum infertility and is known to be related to breast-feeding frequency and duration, but the exact role of complementary feeding of the infant has not been clearly defined. Data on LA were collected during and after a 2-mo intervention trial in which low-income Honduran women who had breast-fed fully for 4 mo were randomly assigned to one of three groups: continued full breast-feeding until 6 mo (FBF, n = 50), introduction of complementary foods at 4 mo with ad libitum breast-feeding from 4 to 6 mo (SF, n = 47), or introduction of complementary foods at 4 mo with maintenance of baseline breast-feeding frequency from 4 to 6 mo (SF-M, n = 44). Women were followed up until the infant was 12 mo of age, or later if menses had not occurred by then. All but six of the women continued to breast-feed for > or = 12 mo. With the exclusion of those whose menses returned before 18 wk postpartum (which could not have been due to the intervention), the proportion of women who were amenorrheic at 6 mo was 64.5% in the SF group, 80.0% in the FBF group, and 85.7% in the SF-M group (chi-square test = 4.13, P = 0.02; one-tailed test with the latter two groups combined). The total duration of LA did not differ significantly among groups. The most significant determinant of LA was time spent breast-feeding (min/d), which was in turn negatively associated (P = 0.06) with the infant's energy intake from complementary foods in regression analyses. These results indicate that there is a significant effect of introducing foods at 4 mo on the likelihood of amenorrhea at 6 mo postpartum, but not thereafter, and that this effect is not seen in mothers who maintain breast-feeding frequency.

Effects of age of introduction of complementary foods on iron status of breast-fed infants in Honduras.

To evaluate the effect of introducing complementary foods before 6 mo of age, we randomly assigned 164 infants who had been exclusively breast-fed for 4 mo to continue being exclusively breast-fed until 6 mo (EBF group) or to receive iron-fortified foods in addition to breast milk from 4 to 6 mo (BF+SF group). At 6 mo, the BF+SF group had higher mean iron intake (4 mg/d compared with 0.2 mg/d in EBF infants) and higher hemoglobin, hematocrit, and ferritin values than the EBF group (P < 0.05). The percentage with low hemoglobin (< 103 g/L) did not differ significantly between groups, but fewer infants in the BF+SF group had a low hematocrit (< 0.33; 21.4% compared with 32.0%, respectively; P < 0.05). The percentage of infants with ferritin concentrations < 12 microg/L at 6 mo was lower than the percentage with low hemoglobin or hematocrit, raising questions about the validity of the cutoffs at this age. Infants at greatest risk for anemia and low ferritin were those with birth weights < 2500 g; no infant with a birth weight > 3000 g had a low ferritin value at 6 mo. We conclude that the risk of iron deficiency is low among infants with birth weights > 3000 g who are exclusively breast-fed for 6 mo. Iron drops are recommended for low-birth-weight infants; for breast-fed infants with birth weights between 2500 and 3000 g, further research is needed to determine whether iron drops are more effective than complementary foods for preventing iron deficiency before 6 mo.

Age of introduction of complementary foods and growth of term, low-birth-weight, breast-fed infants: a randomized intervention study in Honduras.

BACKGROUND: The optimal age at which to introduce complementary foods is a topic of considerable debate. OBJECTIVE: This study was designed to evaluate this issue in a nutritionally vulnerable population in Honduras. DESIGN: Mothers of low-birth-weight (1500-2500 g) term (ie, small-for-gestational-age) infants were recruited in the hospital and assisted with exclusive breast-feeding during the first 4 mo. At 4 mo, mothers were randomly assigned to either continue exclusive breast-feeding to 6 mo (EBF; n = 59) or to feed complementary solid foods (jarred rice cereal, chicken, and fruit and vegetables) twice daily from 4 to 6 mo while continuing to breast-feed at their initial frequency (SF; n = 60). At 4 and 6 mo, breast milk and total energy intake were measured for a nonrandom subsample (those who could stay overnight in a central unit: 32 EBF and 31 SF). RESULTS: At 4 mo, breast milk intake in the subsample was not significantly different between groups (EBF: 729 +/- 135 g/d; SF: 683 +/- 151 g/d: P >0.2); from 4 to 6 mo it increased (by 28 g/d) in the EBF group but decreased (by 39 g/d) in the SF group (P < 0.005). Nonetheless, total energy intake (including solid foods) increased more from 4 to 6 mo in the SF than in the EBF group. However, there were no significant differences between groups in weight or length gain during the intervention or subsequently (6-12 mo). CONCLUSION: There was no growth advantage of complementary feeding of small-for-gestational-age, breast-fed infants between 4 and 6 mo of age.

Maternal anthropometric status and lactation performance in a low-income Honduran population: evidence for the role of infants.

As part of a study on the optimal timing of complementary feeding in Honduras, we assessed breast milk volume and composition at 4, 5, and 6 mo in 141 low-income women who were randomly assigned to exclusively breast-feed for the first 6 mo or to complement breast milk with prepared solid foods beginning at 4 mo. Milk volume averaged 797 +/- 139 g/d at 4 mo. Maternal body mass index was positively associated with infant birth weight and milk energy density. In multivariate analyses in which group assignment was controlled for, milk volume was positively associated with birth weight but negatively associated with milk energy density. Infant breast milk energy intake was positively associated with birth weight and milk energy density. Maternal anthropometric status was not a significant predictor of milk volume or infant energy intake when birth weight and milk energy density were included in the models. These results indicate that infant characteristics, such as birth weight and the ability to self-regulate intake in response to milk energy density, mediate the relationship between maternal anthropometric status and lactation performance.

Determinants of growth from birth to 12 months among breast-fed Honduran infants in relation to age of introduction of complementary foods.

OBJECTIVES: To evaluate the impact of introducing complementary foods to exclusively breast-fed infants at 4 vs 6 months on growth from 6 to 12 months, and to compare growth patterns of Honduran infants with those of breast-fed infants in the United States. DESIGN: Randomized intervention trial from 4 to 6 months and longitudinal study of infants from birth to 12 months. SETTING: Low-income communities in San Pedro Sula, Honduras. SUBJECTS: Primiparous, breast-feeding mothers and their infants (n = 141) recruited from public maternity hospitals. INTERVENTION: Infants were randomly assigned to exclusive breast-feeding to 6 months, or exclusive breast-feeding with addition of hygienically prepared, nutritionally adequate complementary foods at 4 months, with or without maintenance of baseline breast-feeding frequency. After 6 months, mothers continued to breast-feed and also fed their infants home-prepared foods after receiving instruction in appropriate feeding practices. OUTCOME MEASURES: Infant weight was measured monthly during the first year of life and infant length monthly from 4 to 12 months. STATISTICAL ANALYSIS: Growth parameters were compared between the Honduran and US cohorts using multiple-regression and repeated-measures analysis of variance. Stepwise multiple regression was used to identify determinants of infant growth. RESULTS: There were no differences in growth patterns by intervention group. Mean birth weight of the Honduran infants was significantly less than that of a cohort of breast-fed infants in an affluent US population (n = 46) (2889 +/- 482 vs 3611 +/- 509 g), but the Honduran infants exhibited rapid catch up in weight in the first few months of life, and the cohorts were similar in weight by 3 months. Mean weight and length gain were similar to those of the US cohort from 4 to 9 months but were lower from 9 to 12 months. Mean length for age was significantly less than that of the US cohort from 4 to 12 months; this was attributable to the difference in maternal height (12 cm shorter in Honduras on average). Within the Honduran cohort, growth velocity of low birth weight infants (< 2500 g; n = 28) was similar to that of their normal birth weight peers; thus, the former subgroup remained smaller than the latter throughout the first year of life. CONCLUSIONS: In poor populations, when breast-feeding is exclusive for the first 4 to 6 months, continues from 6 to 12 months, and is accompanied by generally adequate complementary foods, faltering in weight does not occur before 9 months among infants born with birth weights of more than 2500 g.

Promoting exclusive breastfeeding for 4-6 months in Honduras: attitudes of mothers and barriers to compliance.

Prospective and retrospective data on maternal attitudes and obstacles to exclusive breastfeeding (EBF) were collected from Honduran mothers of low birthweight (1500-2500 g), term infants who were enrolled in an intervention study to compare infant outcomes in those who were randomly assigned to breastfeed exclusively for either 4 or 6 months. Perceived advantages of EBF were that it was easier, more practical and economical, and resulted in better infant health and growth. Disadvantages included the perceived time demand, concerns that the infant would accept solids less readily, and fears that breast milk alone was insufficient. The majority of study participants said that they would choose to exclusively breastfeed their next infant to 6 months. Although there were many obstacles to EBF, particularly in the first few weeks, women who persevered became enthusiastic proponents of EBF. Messages to promote EBF need to target the entire community, not just mothers, and should focus on addressing common misconceptions and alerting women to potential problems before they occur.

Exclusively breastfed, low birthweight term infants do not need supplemental water.

UNLABELLED: Breast milk intake, urine volume and urine-specific gravity (USG) of exclusively breastfed, low birthweight (LBW) term male infants in Honduras were measured during 8-h periods at 2 (n = 59) and 8 (n = 68) wk of age. Ambient temperature was 22-36 degrees C and relative humidity was 37-86%. Maximum USG ranged from 1.001 to 1.012, all within normal limits. CONCLUSIONS: We conclude that supplemental water is not required for exclusively breastfed, LBW term infants, even in hot conditions.

Effects of age of introduction of complementary foods on infant breast milk intake, total energy intake, and growth: a randomised intervention study in Honduras.

In developing countries, the age at which breastfed infants are first given complementary foods is of public health importance because of the risk of diarrhoeal disease from contaminated weaning foods, and the potential risk of growth faltering if foods are inappropriately delayed. To evaluate whether there are any advantage of complementary feeding prior to 6 months, low-income primiparous mothers who had exclusively breastfed for 4 months were randomly assigned to one of 3 groups: continued exclusive breastfeeding to 6 months (EBF) (n = 50); introduction of complementary foods at 4 months with ad libitum nursing from 4-6 months (SF) (n = 47); and introduction of complementary foods at 4 months, with maintenance of baseline nursing frequency from 4-6 months (SF-M) (n = 44). Baby foods in jars were provided to the SF and SF-M groups from 4 to 6 months. Subjects were visited weekly and provided with lactation guidance; at 4, 5, and 6 months measurements were made of infant intake and breast milk composition. At 4 months, breast milk intake averaged 797 (139) g per day (no difference among groups). Between 4 and 6 months, breast milk intake was unchanged in EBF infants (+6) but decreased in the SF (-103), and SF-M (-62) groups (p < 0.001). Change in total energy intake (including solid foods) and infant weight and length gain did not differ significantly between groups. Weight and length gain from 4-6 months were comparable to those of breastfed infants in an affluent USA population. The results indicate that breastfed infants self-regulate their total energy intake when other foods are introduced. As a result, there is no advantage in introducing complementary foods before 6 months in this population, whereas there may be disadvantages if there is increased exposure to contaminated weaning foods.

Delaying the introduction of complementary food until 6 months does not affect appetite or mother's report of food acceptance of breast-fed infants from 6 to 12 months in a low income, Honduran population.

Low income, primiparous mothers who had exclusively breast-fed for 4 mo were randomly assigned to one of three groups: 1) continued exclusive breast-feeding to 6 mo (EBF), 2) introduction of complementary foods at 4 mo, with ad libitum nursing 4-6 mo (SF), and 3) introduction of complementary foods at 4 mo, with maintenance of base-line nursing frequency 4-6 mo (SF-M). After the intervention phase (4-6 mo; n= 141), home visits were conducted for a subsample at 9 (n = 60) and 12 (n = 123) mo. At each visit, an observer recorded infant food intake at the midday meal and interviewed the mother regarding usual feeding patterns and the infant's acceptance of 20 common food items. All but two infants (1.5%) were breast-fed to 9 mo and all but eight (6%) to 12 mo. There were no significant differences among groups in breast-feeding frequency, amount or number of foods consumed at the midday meal, percentage of food offered that was consumed, usual daily number of meals and snacks, number of food groups consumed, or overall food acceptance score. Frequency of consumption of foods from eight different food groups (dairy, meats, eggs, grains, beans, fruits, vegetables, tubers) was not significantly different among groups except that, at 9 mo only, the SF group (but not the SF-M group) consumed more vegetables than did the EBF group. These results indicate that delaying the introduction of complementary foods until 6 mo does not adversely affect appetite or food acceptance among breast-fed infants.

PIP: Low-income primiparous mothers who had breast fed exclusively for 4 months were randomly assigned to one of three groups: 1) continued exclusive breast feeding (EBF) to 6 months; 2) introduction of complementary foods at 4 months with ad libitum nursing 4-6 months (SF); and 3) introduction of complementary foods at 4 months with maintenance of baseline nursing frequency 4-6 months (SF-M). After the intervention phase (4-6 months; n = 141), home visits were conducted for a subsample at 9 (n = 60) and 12 (n = 123) months. At each visit, an observer recorded infant food intake at the midday meal and interviewed the mother regarding usual feeding patterns and the infant's acceptance of 20 common food items. All but two infants (1.5%) were breast fed to 9 months and all but eight (6%) to 12 months. There were no significant differences among groups in breast-feeding frequency, amount or number of foods consumed at the midday meal, percentage of food offered that was consumed, usual daily number of meals and snacks, number of food groups consumed, or overall food acceptance score. Frequency of consumption of foods from eight different food groups (dairy, meats, eggs, grains, beans, fruits, vegetables, tubers) was not significantly different among groups except that, at 9 months only, the SF group (but not the SF-M group) consumed more vegetables than did the EBF group. The SF groups initially accepted carrots more readily than did the other two groups (p .05), and the SF and SF-M groups initially accepted potato more readily than did the EBF group (p .05). The average number of food groups from which foods were consumed at least twice per week was significantly higher in the SF group (but not the Sf-M group) than in EBF group at 9 months, but not at 12 months. Delaying the introduction of complementary foods until 6 months does not adversely affect appetite or food acceptance among breast-fed infants.

Do exclusively breast-fed infants require extra protein?

It has been argued that the growth rate of exclusively breast-fed infants may be limited by their protein intake. This issue was examined using data from an intervention study in Honduras in which infants were randomly assigned to be exclusively breast-fed for the first 6 mo (EBF; n = 50), or to receive preprepared solid foods (including egg yolk) in addition to breast milk beginning at 4 mo (n = 91). Neither weight gain nor length gain from 4 to 6 mo differed between groups despite a 20% higher protein intake (as well as significantly higher intakes of iron, zinc, calcium, vitamin A, and riboflavine) in the latter group. The 20 infants with the highest protein intakes in that group were matched to 20 EBF infants on the basis of energy intake; protein intake was 1.46 +/- 0.09 versus 1.10 +/- 0.17 g/kg/d, respectively (p < 0.001), but growth rate did not differ between groups. Similarly, the 20 infants with the lowest protein intakes in the EBF group were matched (by energy intake) to 20 infants given solid foods; protein intake was very low in the former compared with the latter (0.81 +/- 0.13 versus 1.04 +/- 0.20 g/kg/d; p < 0.001), yet there was still no difference in growth. Infant morbidity was relatively low and did not influence the results. These analyses indicate that protein intake is not likely to be a limiting factor with regard to growth of breast-fed infants from 4 to 6 mo of age.

Effects of exclusive breastfeeding for four versus six months on maternal nutritional status and infant motor development: results of two randomized trials in Honduras.

To examine whether the duration of exclusive breastfeeding affects maternal nutrition or infant motor development, we examined data from two studies in Honduras: the first with 141 infants of low-income primiparous women and the second with 119 term, low birth weight infants. In both studies, infants were exclusively breastfed for 4 mo and then randomly assigned to continue exclusive breastfeeding (EBF) until 6 mo or to receive high-quality, hygienic solid foods (SF) in addition to breast milk between 4 and 6 mo. Maternal weight loss between 4 and 6 mo was significantly greater in the exclusive breastfeeding group (EBF) group than in the group(s) given solid foods (SF) in study 1 (-0.7 +/- 1.5 versus -0.1 +/- 1.7 kg, P < 0.05) but not in study 2. The estimated average additional nutritional burden of continuing to exclusively breastfeed until 6 mo was small, representing only 0.1-6.0% of the recommended dietary allowance for energy, vitamin A, calcium and iron. Women in the EBF group were more likely to be amenorrheic at 6 mo than women in the SF group, which conserves nutrients such as iron. In both studies, few women (10-11%) were thin (body mass index <19 kg/m(2)), so the additional weight loss in the EBF group in study 1 was unlikely to have been detrimental. Infants in the EBF group crawled sooner (both studies) and were more likely to be walking by 12 mo (study 1) than infants in the SF group. Taken together with our previous findings, these results indicate that the advantages of exclusive breastfeeding during this interval appear to outweigh any potential disadvantages in this setting.

Iron supplementation of breast-fed Honduran and Swedish infants from 4 to 9 months of age.

OBJECTIVE: The objective was to study the effects of iron supplementation on hemoglobin and iron status in 2 different populations. STUDY DESIGN: In a randomized, placebo-controlled, masked clinical trial, we assigned term Swedish (n = 101) and Honduran (n = 131) infants to 3 groups at 4 months of age: (1) iron supplements, 1 mg/kg/d, from 4 to 9 months, (2) placebo, 4 to 6 months and iron, 6 to 9 months, and (3) placebo, 4 to 9 months. All infants were breast-fed exclusively to 6 months and partially to 9 months. RESULTS: From 4 to 6 months, the effect of iron (group 1 vs 2 + 3) was significant and similar in both populations for hemoglobin, ferritin, and zinc protoporphyrin. From 6 to 9 months, the effect (group 2 vs group 3) was significant and similar at both sites for all iron status variables except hemoglobin, for which there was a significant effect only in Honduras. In Honduras, the prevalence of iron deficiency anemia at 9 months was 29% in the placebo group and 9% in the supplemented groups. In Sweden, iron supplements caused no reduction in the already low prevalence of iron deficiency anemia at 9 months (<3%). CONCLUSION: Iron supplementation from 4 to 9 months or 6 to 9 months significantly reduced iron deficiency anemia in Honduran breast-fed infants. The unexpected hemoglobin response at 4 to 6 months in both populations suggests that regulation of hemoglobin synthesis is immature at this age.