An evaluation of patient comfort levels during expression with a modified pumping program: a prospective proof of concept study.

Introduction: This study aimed to assess if the implementation of a gentle transition of vacuum mode into a breast pump suction pattern commonly used to initiate milk production would improve user comfort while expressing during the first four days postpartum. Methods: This prospective study was conducted at OLVG hospital in the Netherlands in two sequential phases. Breastfeeding patients delivering >36 weeks gestation with an infant aged ≤96 h old and a clinical indication to express milk with a breast pump were recruited. Intervention group 1 (n = 40) used a hospital-grade electric breast pump with a standard breast pump suction pattern. Intervention group 2 used a hospital-grade electric breast pump with a modified breast pump suction pattern (n = 40). The primary outcome was an objective assessment of comfort as measured by participants' need to reduce vacuum level during the 20 min test session. Secondary outcomes included the total expression volume (ml) in 20 min pumping. Results: The study found that the primary outcome of comfort was significantly improved with the modified breast pump suction pattern compared to the standard pattern (OR 1.29, 95% CI 1.08 to 1.6) with 86% vs. 67% of participants not needing to reduce applied vacuum levels. The amount of milk expressed did not differ significantly between phases (group 1: 7.6 ml (2.7-25.5 ml), group 2: 12.0 ml (1.2-31.5 ml), p = 0.43). Discussion: This study is the first to demonstrate an improvement in user comfort driven by the implementation of gentle transitions in vacuum modes in a commonly used breast pump suction pattern. Research into this novel population combining both pumping and breastfeeding in the first days after birth offers new unique insights on the requirements of breast pump suction patterns. Trial registration: Registered on clinical trials.gov NCT04619212. Date of registration November 6, 2020.

Breast shield design impacts milk removal dynamics during pumping: A randomized controlled non-inferiority trial.

INTRODUCTION: While many studies have investigated the importance of optimizing pumping patterns for milk removal, the influence of breast shield design on milk removal has not been the focus of extensive investigation. This study aimed to determine the effectiveness of breast shields with either a 105° or a 90° flange opening angle on breast drainage and milk volume expressed during pumping. MATERIAL AND METHODS: This study was a cross-over, randomized controlled non-inferiority trial (Registration; NCT03091985). Mothers (n = 49) of breastfeeding infants participated in the study over two study sessions. Participants were randomly assigned to pump both breasts simultaneously for 15 minutes with either the 105° or 90° breast shield in the first session, and the other shield in the second session. Effectiveness (breast drainage) and efficiency (volume expressed) of both breast shields were assessed after 15 minutes of pumping. Intention-to-treat and per protocol analyses were performed to determine if the 105° breast shield was non-inferior to the 90° breast shield for breast drainage and volume expressed. Perceived comfort was assessed via questionnaire. RESULTS: The 105° breast shield was both non-inferior and superior compared to the standard 90° shield for breast drainage (intention-to-treat, 3.87% (0.01-7.72), P = .049) and volume expressed (intention-to-treat, 9.14 mL (1.37-16.91), P=.02). In addition, the 105° shield was rated as feeling more comfortable (P < .001) and as having an improved fit to the breast (P < .001) compared to the 90° shield. CONCLUSIONS: Expressing with the 105° breast shield was more efficient, effective and comfortable compared to the 90° shield. Breast shield design can significantly impact pumping outcomes, and an opening angle of 105° improves both the dynamics and comfort of milk removal.

Milk ejection patterns remain consistent during the first and second lactations.

OBJECTIVE: Milk ejection is a critical physiological process for successful lactation in humans and without it little milk can be removed. Individual milk ejection patterns have been shown to remain consistent between breasts at different lactation stages and using different vacuum patterns with an electric breast pump. Little is known about the milk ejection characteristics during the second lactation period in the same mother. The objective of this study was to examine milk ejection characteristics in the same woman over two lactations. METHODS: One mother took part in two pumping studies during consecutive lactations. One pumping study examined milk ejection characteristics during simultaneous breast expression during the first lactation. The second pumping study (second lactation) used two different pumping patterns. Three distinct milk ejections were measured during each pumping session. RESULTS: Measurements of milk flow were used to compare the duration and time taken to reach the peak of each milk ejection for two pumping sessions from each of the lactations. There were no significant differences in milk ejection characteristics between breasts, using different pumping patterns, or between lactations in this mother (P > .05). CONCLUSION: Milk ejection appears to be a physiological response that is consistent across consecutive lactations within the same mother. This suggests that milk ejection characteristics are established during or prior to the first lactation. The infant appears to have little influence on the milk ejection characteristics of the mother.

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.

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.

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.

Blood flow characteristics of the human lactating breast.

BACKGROUND: Despite the increased metabolic activity of the lactating breast, no studies have been carried out to determine mammary blood flow (MBF) parameters or the relationship between MBF and milk production in women. The aim of this study was to measure the MBF in the internal mammary artery (IMA) and lateral thoracic artery (LTA) of lactating women and determine if these were related to milk production. METHODS: Blood flow in the IMA and LTA was measured with color Doppler ultrasound in 55 lactating women. Twenty-four-hour milk production was determined with the test-weigh method. RESULTS: IMA contributed the greater proportion of blood flow to the lactating breast (70%). MBF was highly variable between women but consistent between the left (126 L/24 h; interquartile range, 76-169) and right (110 L/24 h) breasts. No relationship between MBF and milk production was demonstrated. For 3 women, MBF was markedly reduced in 1 breast that was synthesizing almost no milk compared to the other that was producing a normal volume of milk. DISCUSSION: Although no relationship between MBF and milk production was found, the substantial reduction in blood flow in the breasts of lactating women producing almost no milk suggests a threshold below which milk production is compromised. CONCLUSION: Doppler ultrasound did not demonstrate a relationship between MBF and milk production in lactating women. Further investigation is required to fully understand the role of blood flow in milk synthesis.

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 mother's 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.

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.

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.

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

BACKGROUND: Milk 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. METHODS: Increased 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. RESULTS: Increased 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. CONCLUSION: The 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.

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 degrees 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 degrees 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 degrees 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.

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. METHODS: All medical pregnancy terminations for fetal anomaly performed after 14 weeks gestation from January 1997 to December 2006 were identified and the frequency of autopsy ascertained. The prenatal diagnosis prompting the termination was then compared with the autopsy data, and a diagnostic valuation was determined. The potential autopsy value ranged from no additional information provided, minor added value, significant added value, major added value to non-confirmation of the prenatal findings. RESULTS: During the ten-year study period, there were 1012 consecutive terminations for fetal abnormality. The principal indications for termination were: karyotypic (38.4%); neural tube defects (16.1%); cardiac (10.3%) and cerebral anomalies (7.5%). Autopsy was performed in 809 cases (79.9%). The autopsy rate progressively declined from 95.1% in 1997 to 67.5% in 2006 (P<0.001). Women declining autopsy were older (31 years (26,35) vs 32 years (27,37), P=0.005) and more likely to have a fetal chromosomal abnormality (30.6% vs 69.9%, P<0.001) (autopsy vs no-autopsy). In euploid cases, autopsy confirmed the prenatal diagnosis with no additional information in 63.5% (357 of 562). In 1.1% (six cases), autopsy added major diagnostic information, and in 15.1% (85 cases), significant information was provided. CONCLUSIONS: Although contemporary prenatal testing has improved the recognition of fetal abnormalities, autopsy remains a valued tool by providing diagnosis or clarification of some prenatal findings in 16% of cases. Fetal autopsy rates are declining and this trend may lead to a loss of diagnostic and recurrence risk-counselling information.