Danielle K. Prime

Retention of the Immunological Proteins of Pasteurized Human Milk in Relation to Pasteurizer Design and Practice

Pasteurizing donor human milk inactivates bacteria that may be of concern to the preterm infant. However, current practice for Holder Pasteurization (62.5°C for 30 min) is detrimental to the bioactivity of human milk. An experimental pasteurizer was used to determine the maximum temperature at which 90% of secretory IgA, lysozyme, and lactoferrin were retained and whether this temperature was capable of inactivating five common bacterial contaminants. The retention of these proteins was also compared using a commercially available bottle immersion or holding chamber system. After pasteurization at 62.5°C for 30 min, the retention across all three systems was 72.3 ± 3.6%, 21.8 ± 3.3%, and 39.4 ± 11.5% for sIgA, lactoferrin, and lysozyme, respectively (n = 22). The retention of all three proteins was at least 90% when human milk was pasteurized at 57°C for 30 min, and this temperature was also effective at removing 99.9% of all inoculated bacterial species. In addition, human milk that was pasteurized in the experimental system had a significantly higher proportion of lysozyme compared with samples pasteurized in the bottle immersion system. These findings suggest that optimizing pasteurization temperature and improving pasteurizer design enhances the quality of pasteurized donor human milk.

Variation in fat, lactose, and protein composition in breast milk over 24 hours associations with infant feeding patterns

Background: Data regarding the association between breast milk composition and infant feeding patterns (frequency and amount of breast milk taken) would help in understanding the regulation of food intake in breastfed infants. Objective: This study examined the relationship between breast milk macronutrient concentration and patterns of milk intake in breastfeeding infants over a 24-hour breastfeeding period. Methods: Mothers of healthy term infants (n = 15) collected pre- and postfeed breast milk samples from each feed at each breast over a 24-hour period. Breast milk samples were analyzed for fat, lactose, total protein, casein, and whey protein content. The energy content for each feed was calculated. Results: Breastfeeding patterns and milk composition varied greatly between individuals. The fat content of milk significantly differed over 24 hours (P = .01), whereas the concentration of lactose and protein content remained the same. The mean 24-hour total protein, whey, and casein intake was inversely (P < .01), whereas lactose concentration was positively (P = .03) related to the number of breast feeds per day. No relationship was seen either between fat or energy content and feeding patterns. The mean (SD) concentration of fat, lactose, and total protein over the 24-hour period was 43 (12) g/L, 68 (7) g/L, and 13 (2) g/L, respectively. Conclusion: The association between milk protein intake and the breastfeeding frequency suggests that the protein intake may play a role in infant appetite control.

Principles for Maintaining or Increasing Breast Milk Production

Breastfeeding rates in many developed countries remain low, and maternal perception of insufficient milk production is a major contributing factor. Mothers with a perception of insufficient milk should be advised that normal breastfeeding frequencies, suckling times, and amounts are very variable. If objective assessment confirms insufficient milk production, mothers should ensure optimal milk removal frequency and thorough breast drainage. In addition, galactogogues can be prescribed. Understanding physiological principles underlying milk production will help clinicians reassure and assist mothers.

The role of autopsy following pregnancy termination for fetal abnormality

Objective:  To review the frequency of autopsy following pregnancy termination for fetal anomaly and its contribution to subsequent counselling.

Using milk flow rate to investigate milk ejection in the left and right breasts during simultaneous breast expression in women.

BackgroundMilk ejection is essential for a successful lactation, however techniques to measure milk ejection in women are often complex and invasive. Recent research has demonstrated that at milk ejection, milk duct diameter increased in the breast (measured by ultrasound) at the same time as milk flow rate increased (measured using a weigh balance). This study aimed to evaluate a purpose-built continuous weigh balance (Showmilk, Medela AG) to measure changes in milk flow rate from the breast to identify milk ejections during milk expression. In addition, the Showmilk was used to determine if milk ejection occurred simultaneously in both breasts during double pumping.MethodsIncreased milk flow rates during single pumping were compared to simultaneous ultrasound measurements of increased milk duct diameters in 14 mothers. In addition, increases in milk flow rate were compared between the left and right breasts of 28 mothers during double pumping for 15 minutes with two separate electric breast pumps attached to two Showmilks to record milk flow rate.ResultsIncreased milk flow rates were associated with increased milk duct diameters during single pumping. The mean number of milk ejections was not different between the Showmilk (4.2 ± 2.0) and ultrasound (4.5 ± 1.5) techniques. Overall, 67 milk ejections were measured and of these, 48 (72%) were identified by both techniques. The left and right breasts responded synchronously with 95.5% of the flow rate increases corresponding between the breasts. The mean number of milk ejections identified by an increase in milk flow rate during double pumping was 5.1 ± 1.7 and 5.0 ± 1.7 for the left and right breasts, respectively. In addition, mothers chose the same expression vacuum for the left (-198 ± 31 mmHg) and right (193 ± 33 mmHg) breasts.ConclusionThe Showmilk can simply and non-invasively record milk ejections by measuring increases in milk flow rate that correspond with increases in milk duct diameter. For the first time measurement of milk flow rate has been used to confirm that milk ejections occur simultaneously in the left and right breasts during double pumping. The use of the Showmilk will facilitate further research into the relationship of milk ejection and milk removal.

Investigation of Short-term Variations in Term Breast Milk Composition during Repeated Breast Expression Sessions

Background: Breast milk composition can be affected by several factors, and it can exhibit short-term (weekly) variations. Investigating variations in breast milk composition is important to accurately estimate nutrient requirements of the infant. Objective: To investigate short-term changes in breast milk composition between left and right breasts, over a 3-week period within the first 6 months of lactation. Methods: The left and right breasts of the mothers of healthy, term infants (n = 23) were simultaneously expressed with an electric breast pump for 15 minutes, on 3 occasions within 3 weeks. Milk samples (5 mL) were collected from the total expression volume of each breast at each session. The macronutrient contents, total solids, and energy content were determined using a mid-infrared human milk analyzer. Mothers (n = 17) measured their 24-hour milk production, and the average 24-hour fat contents were also determined. Results: Over the 3 weekly sessions, no significant changes were found in macronutrient contents. On average, total solids (P = .04) and energy (P = .04) decreased by week 3 of follow-up sessions from 14 to 13 g/100 mL and from 82 to 76 Kcal/100 mL, respectively; however, these changes became insignificant when expression volume was taken into account. The macronutrient concentration was similar for the left and right breasts; however, milk composition varied markedly between mothers. Furthermore, average 24-hour fat content was significantly lower than the mean fat content from a single expression session (P < .01). Conclusion: Our findings highlight that when determining the nutritional adequacy of a mother’s milk, assuming an average concentration requires caution. The study findings illustrate the importance of using average 24-hour fat content of milk to obtain representative measures of infant energy intake.

Simultaneous Breast Expression in Breastfeeding Women Is More Efficacious Than Sequential Breast Expression

INTRODUCTION Simultaneous (SIM) breast expression saves mothers time compared with sequential (SEQ) expression, but it remains unclear whether the two methods differ in milk output efficiency and efficacy. SUBJECTS AND METHODS The Showmilk device (Medela AG, Baar, Switzerland) was used to measure milk output and milk ejection during breast expression (electric pump) in 31 Australian breastfeeding mothers of term infants (median age, 19 weeks [interquartile range, 10-33 weeks]). The order of expression type (SIM/SEQ) and breast (left/right) was randomized. RESULTS SIM expression yielded more milk ejections (p ≤ 0.001) and greater amounts of milk at 2, 5, and 10 minutes (p ≤ 0.01) and removed a greater total amount of milk (p ≤ 0.01) and percentage of available milk (p<0.05) than SEQ expression. After SIM expression the cream content of both the overall (8.3% [p ≤ 0.05]) and postexpression (12.6% [p ≤ 0.001]) milk were greater. During SEQ expression, the breast expressed first had a shorter time to 50% and 80% of the total amount of milk than the breast expressed second (p ≤ 0.05), but, overall, a similar percentage of available milk was removed from both breasts. CONCLUSIONS SIM expression stimulated more milk ejections and was a more efficient and efficacious method of expression, yielding milk with a higher energy content.

Comparison of the patterns of milk ejection during repeated breast expression sessions in women.

BACKGROUND This study aimed to investigate the consistency of milk ejections and milk expression characteristics within mothers at repeated expression sessions. METHODS Twenty-five breastfeeding mothers expressed their breasts simultaneously on three occasions within 3 weeks, and follow-up visits were performed at 6, 9, and 12 months of lactation. During the 15-minute expression, milk was collected onto a continuous weigh balance to measure milk flow rate. RESULTS The number of milk ejections was similar at the three sessions (5.1±2.0), decreasing at the 12-month follow-up (3.3±1.2). Mothers had a similar pattern of milk ejection at each session. The time that each milk ejection occurred was consistent for the first 9 months of lactation. Of the four milk ejection patterns identified, each removed a similar percentage of available milk but varied in the time to reach 80% of the total expression volume. The first two milk ejections produced the greatest percentage (62%) of total milk volume during breast expression. CONCLUSIONS For each individual mother, the timing, pattern, and number of milk ejections were consistent, suggesting a predetermined release of oxytocin. In light of the innate oxytocin release and milk removal characteristics in women, there is potential for individual tailoring of the duration of expression.

Investigation of Short-term Variations in Casein and Whey Proteins in Breast Milk of Term Mothers

Objectives: We investigated changes in breast milk whey and casein proteins, between fore and hind milk during breast expression, between breasts and within 24-hour period during breast-feeding. This has implications for developing an appropriate sampling protocol for investigating the influence of milk composition on gastric emptying and infants’ feeding behaviour. Methods: Breast milk samples were collected from mothers (n = 25) of healthy term infants ages 1 to 8 months. A total of 17 mothers provided fore and hind milk samples, which were collected during simultaneous expression of both breasts. Fifteen mothers provided samples from each breast-feed during 24-hour period, of which samples were selected from 4 time points (morning, day, evening, night). Whey and casein were isolated from skim milk, and protein concentration of the skim, whey, and casein fractions were determined. Results: Mean protein concentrations were found to be 13.5 ± 2.1 (skim milk), 7.6 ± 1.5 (whey), and 3.4 ± 0.97 g/L (casein). Protein concentrations were not significantly different between fore and hind milk. During a 24-hour period, no significant differences were found in protein concentration of any fraction at the 4 time points or between left and right breasts. Large variations were seen between mothers with coefficient of variances of 15.5%, 19.8%, and 28.4% for skim milk, whey, and casein, respectively. Conclusions: Although there was wide variation between mothers, the small variations within mothers indicate that for sampling purposes, a single breast milk sample (fore or hind from each breast at any time point of the day) will be representative of that mothers protein concentration of skim, whey, and casein fractions for that day.

Dynamics of Milk Removal During Simultaneous Breast Expression in Women

OBJECTIVE To investigate the dynamics of milk removal during breast expression. SUBJECTS AND METHODS This study used a continuous weighing balance to determine changes in milk flow rate and their relationship to the proportion of milk removed over time and the percentage of the available milk removed during simultaneous expression (15 minutes) of the left and right breasts in 34 mothers of healthy, term, breastfeeding infants. RESULTS Multiple milk ejections (5.1±2.0; range, two to 14) were detected as increases in milk flow rate. A larger total expression volume was associated with a higher maximum milk flow rate (p<0.001). However, 14% less of the available milk was removed for a 100 g increase in available milk (p<0.001). After 2.9±1.4 and 6.0±2.5 minutes, 50% and 80%, respectively, of the total expression volume was removed. Milk flow was more active in the first 7 minutes than the last 7 minutes. At the eighth minute (midpoint), 54±25% of the available milk and 86±9% of the total expression volume were removed. CONCLUSIONS The maximum milk flow rate was predictive of the total volume expressed. After the eighth minute of expression the milk flow rate was reduced. Increasing volumes of milk in the breast were associated with less complete breast emptying. These data suggest that long expression sessions are not required for mothers who are not pump dependent and that extending intervals between expressions results in less effective milk removal.