Electric Breast Pump Research Articles

The Time Course of Human Milk Insulin and Glucose Response to an Oral Glucose Challenge - A Case Study (P11-045-19)

ObjectivesIt is often cited that insulin in human milk (HM) increases postprandially along with maternal serum insulin. However, this response has never been documented in humans, and the characteristics of this increase remain unstudied. MethodsTwo healthy lactating women emptied their breasts after a fast (> 8 hours) using an electric breast pump. After consuming a 50g glucose water, each woman emptied a single breast at 15, 30, 60, 90, and 120 minutes. Skim milk was generated via centrifugation and HM glucose and insulin were measured via hexokinase assay and chemiluminescent immunoassay (Beckman Coulter). At each of these time points maternal blood was collected via finger prick and capillary glucose measured via handheld glucometer. Additional blood was spotted onto a dried blood spot (DBS) card, and maternal insulin was measured from the DBS cards via Ultrasensitive ELISA (Mercodia). ResultsBoth insulin and glucose concentrations rose in HM after the glucose load (Figure A, B). The amplitudes of both HM insulin and glucose were lower than that of maternal circulation. Neither HM insulin nor glucose were correlated with concentrations in maternal blood. However insulin concentrations were tightly correlated with glucose concentrations in both HM (P < 0.0001, R2 = 0.84) and maternal blood (P < 0.001, R2 = 0.72). At 2 hours post-glucose challenge, both maternal blood insulin and glucose had returned to near fasting levels (insulin: 15.1 ± 7.8 μU/mL; glucose: 107 ± 4 mg/dL). However, HM insulin and glucose concentrations remained elevated (Figure A, B). At 2 hours, HM insulin remained 13 times higher than fasting concentrations and HM glucose remained 3.9 times higher than fasting concentrations. ConclusionsTo our knowledge, these are the first data in humans to characterize the time course of HM insulin response to an oral glucose challenge. These data will inform the design of HM composition studies when free-living HM samples are collected. The impact of variation in these components over the day on the recipient infant deserves further research. Funding SourcesInternally Funded. Supporting Tables, Images and/or Graphs▪

Implementation of a Breast Milk Pumping Program for Women Who Give Birth While They Are Incarcerated

Women who give birth during incarceration are very limited in their opportunity, ability, and support to choose breast milk as the preferred food for their newborn. The program’s purpose was to introduce breast milk expression to women who give birth while they are incarcerated. Providing a means to collect, store, and release breast milk not only provides the optimal food source to the newborn but also fosters accountability, parenting, and a focus on health-promotion practices for lactating women. Women who give birth while incarcerated will initiate breastfeeding through breast milk expression, using electric breast pumps provided by the correctional facility. A collaborative agreement between the correctional facility and the health care provider group directed acquisition of breast pumps, education for facility employees and inmates, and provision of lactation specialists for continued guidance and support. As the expectant woman neared her due date, she was encouraged to speak with a breastfeeding advocate about the program. Program facilitators reviewed parameters and expectations with each woman, after which the woman could choose to opt in or decline. Once in the program, a licensed lactation counselor met weekly with each participant to troubleshoot identified issues and concerns. Of 17 births that occurred since the implementation of the program, 6 women chose to participate in the breast milk–expression program. Two of the 6 women were released 6 weeks after childbirth; each reported they planned to continue providing breast milk to their infant. One participant was able to express and have her milk delivered to the NICU for the entire time her infant was hospitalized. The lactation specialist documented participant feedback for use in program evaluation and revision. Incarcerated individuals surrender many allowed freedoms; however, choosing to breastfeed an offspring should not be viewed as a freedom to be lost. Refusing to provide incarcerated women who have recently given birth with the opportunity, resources, and support necessary to supply breast milk to her infant is not only a disservice to the lactating woman but denies the newborn the chance to begin life, growth, and development with the food source recognized as best.

Clinical Investigation to Assess the Performance of the Eureka Electric Breast Pump in Mothers Breastfeeding Their Healthy Term Infant

Clinical Investigation to Assess the Performance of the Eureka Electric Breast Pump in Mothers Breastfeeding Their Healthy Term Infant

Detection of Milk Ejection Using Bioimpedance Spectroscopy in Lactating Women during Milk Expression Using an Electric Breast Pump.

Milk ejection is essential for effective milk removal during breastfeeding and pumping, and for continued milk synthesis. Many women are unable to accurately sense milk ejection to determine whether their infant is receiving milk or, when pumping, to switch the pump to a more effective expression pattern. To determine if changes in bioimpedance parameters are associated with milk ejection in the lactating breast during pumping. 30 lactating women participated in 2 pumping sessions within 2weeks of each other. During pumping the breasts were monitored with bioimpedance spectroscopy (on either the pumped or the non- pumped breast), and milk flow rate and volume were measured simultaneously. All mothers completed 24-h milk productions. Linear mixed effects models were used to determine associations between milk flow rate and bioimpedance changes. Changes in bioimpedance parameters were greater at the first milk ejection when measured on the pumped breast (median (IQR): R zero: -7 (-17, -4,) % (n = 30); R infinity: -8 (-20, -2) % (n = 29); membrane capacitance: -24 (-59, -7) % (n = 27). Changes in bioimpedance detected in the non-pumped breast were lower at the first milk ejection, R zero: -3 (-8, -2) % (n = 25); R infinity: -5 (-8, -2) % (n = 23); membrane capacitance: -9 (-17, 15) % (n = 24). Smaller less consistent decreases in the bioimpedance characteristics were detected at the second milk ejection in both breasts. Bioimpedance parameters showed a consistent decrease associated with the first milk ejection when electrodes were placed on the pumped breast. Smaller decreases were observed when the non-pumped breast was monitored for the first and second milk ejection. There was wide variation in the magnitude of changes observed, and hence further development of the methodology is needed to ensure reliability.

Changes in R0/R∞ ratio and membrane capacitance are associated with milk removal from the breast.

Perceived low milk supply is a common reason for introducing supplementary feeds, which in turn serves to further diminish the milk supply. Current methods of measuring milk production and milk transfer from the breast to the infant are inaccessible to the mothers. There is a need for an inexpensive, portable device to enable mothers to measure milk transfer to either confirm their milk production is adequate or identify breastfeeding issues early. The aim of this study was to examine changes in bioimpedance spectroscopy associated with milk removal from the human lactating breast using an electric breast pump. Thirty lactating women participated in 2 research sessions performed in random order over 2 weeks. Milk flow rate and volume were measured during pumping. All mothers completed 24-hour milk profiles. Breasts were monitored using bioimpedance spectroscopy. Analysis was performed using linear mixed effects models to investigate the relationship between both proportional change in membrane capacitance (Cm) and R0/R∞ with milk removal. There was an inverse relationship between R0/R∞ and milk removed (p<0.001). A positive relationship was also observed between Cm and both volume of milk removed (P<0.001) and percentage of available milk removed (p<0.001). This study has shown that changes in bioimpedance are related to the volume of milk removed from the breast during pumping. This modality may hold promise for the measurement of the effectiveness of the breastfeeding infant in removing milk from the breast.

Pasteurization Preserves IL-8 in Human Milk.

Background: Pasteurized donor human milk is an alternative feeding when mothers' own milk is not available for premature infants. The effects of pasteurization on the host defense properties of human milk are unclear. We investigated the effects of Holder pasteurization on concentrations of anti-inflammatory and pro-inflammatory cytokines in human milk.Objective: To compare concentrations of anti-inflammatory and pro-inflammatory cytokines before and after pasteurization of donor human milk.Study Design: A single milk sample was obtained from each of 24 mothers of premature infants in the neonatal intensive care unit by electric breast pump and was stored at −80°C. At the time of pasteurization, milk samples were thawed and divided into two aliquots. The first aliquot was re-stored at −80°C and the second aliquot was heat-treated at 62.5°C for 30 min and then re-stored at −80°C. At the time of batch cytokine analyses samples were thawed rapidly.Results: Most cytokine concentrations declined following pasteurization. The most prevalent cytokine, IL-8, was preserved (89%) following pasteurization. There were no relationships between gestational age, postnatal age of milk collection, duration of milk storage, and the concentrations cytokines.Conclusion: In contrast to most cytokines after pasteurization, IL-8 is preserved or liberated from another compartment. The maintenance of IL-8 in human milk after pasteurization and the loss of anti-inflammatory cytokines following pasteurization, suggests that the effects of inflammatory activity in pasteurized human milk should be evaluated. These data may account, in part, for the lesser protective effect on the host of pasteurized donor human milk compared with mother's own milk.

Comparison of Breast Milk Compositions Among Mothers Delivering Small-for-Gestational Age, Appropriate-for-Gestational Age, and Large-for-Gestational Age Infants.

The aim of this study was to compare the breast milk compositions of mothers who delivered babies in three different birth weight categories. We collected 75 breast milk samples from mothers of small-for-gestational age (SGA), appropriate-for-gestational age (AGA), and large-for-gestational age (LGA) term infants (25 per group) on the 11th-28th day postpartum using a manual or electric breast pump. Homogenized samples were analyzed using a mid-infrared human milk analyzer within 2 hours of collection, and protein, carbohydrate (CHO), fat, and energy levels were compared. Of 75 participants (median maternal age: 29 years), there was a significant difference in maternal body mass index (BMI), gestational age, and birth weight among the three groups. However, we found no significant variation in breast milk true protein, crude protein, fat, or energy. The CHO composition of breast milk in mothers of SGA infants (7.1 g/100 mL, range: 6.6-7.3 g/100 mL) was significantly lower than that in the AGA (7.3 g/100 mL, range: 7.1-7.5 g/100 mL) and LGA (7.2 g/100 mL, range: 6.7-7.4 g/100 mL) groups. After post hoc multiple comparison, only CHO levels between the SGA and AGA groups were significantly different (p = 0.025), whereas no significant correlation was found between maternal BMI, gestational age, and CHO. The CHO component in breast milk from mothers of SGA infants was significantly lower compared with the AGA and LGA groups, but with no clinical significance. Breast milk compositions of mothers of LGA infants were comparable to those of SGA and AGA infants. Therefore, fetal growth status does not significantly influence maternal breast milk nutrients.

Clinical Quiz: The Strawberry Coloured Breastmilk

A 33 year-old Para 1 complained of strawberry coloured breastmilk for 1 day duration while expressing her breastmilk on the left breast at work. She has been exclusively breastfeeding for the past 6 months and never encountered such incident before. She also felt pain over the left breast. However, there was no lump, nipple crack,abnormal nipple discharges or fever prior to that. She expressed her breastmilk using a double mechanical electric breastpump about five times a day lasting from 10 to 20 mintues per sesion since she returned to work.

Investigating Methods of Estimating the Rate of Synthesis of Breast Milk and Milk Fat

Study objectiveCurrently measurement of the average rate of breast milk synthesis and fat synthesis relies on a 24‐h milk profile (test‐weighing all breastfeeds and expressions over a 24‐h period and collecting small milk samples before and after each breastfeed for the same period). It has been demonstrated that when the breasts are expressed using an electric breast pump each hour, the volume of the fourth expression is equivalent to the hourly rate of milk synthesis. We aimed to confirm this finding, and ascertain if the same technique could be used to estimate the rate of milk fat synthesis.MethodsThe study was approved by the Human Research Ethics Committee of The University of Western Australia and all participants provided written informed consent. Mothers (n = 15) measured their 24‐h milk profile, and then expressed their breast(s) using a Medela Symphony breast pump for 10 min on arrival at the research room, and 1, 2 and 3 hours later. The volume of milk expressed each time was measured and small (&lt;1 mL) milk samples collected before and after each expression. The creamatocrit of each sample was measured and converted to fat using the formula fat (g.L−1) = 3.968 + (5.917*creamatocrit). Linear mixed models were used to compare the volumes and fat content at each hourly expression with the hourly milk yield and fat synthesis from the 24‐h milk profile. Random effect was the mother.ResultsThe mean rates of milk synthesis were 17.8 mL.h−1 (sem 2.0) and 19.0 mL.h−1 (sem 2.0) for 24‐h milk profile and fourth expression, respectively, and there was a significant relationship between the two measurements (P=0.002). The slope of the regression was 0.66 with a confidence interval of 0.32 – 1.00). The mean rates of fat synthesis were 0.75 g.h−1 (sem 0.06) and 0.96 g.h−1 (sem 0.13) for 24‐h milk profile and fourth expression, respectively, and there was a significant relationship between the two measurements (P=0.039). The slope of the regression was 1.14 with a confidence interval of 0.20 – 2.08.ConclusionThese data confirm that the fourth hourly expression can be used to estimate the average rate of breast milk synthesis for individuals. However, while there is an overall relationship between the two methods for estimating the rate of synthesis of milk fat, the wide confidence interval for the slope of the regression implies that this technique is less useful for individuals.Support or Funding InformationUnrestricted research grant from Medela AG

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

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. 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. 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). 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.

An Adoptive Mother Who Became a Human Milk Donor.

Inducing lactation in the absence of pregnancy (nonpuerperal lactation) is not always successful and, in many cases, only partial breastfeeding is achieved. Different protocols have been described, but scientific evidence and research are lacking in this area. The authors describe the case of a woman with a history of a miscarriage, for whom the lactation induction process was so effective that she became a milk donor even before she received her adopted child. She had not previously used hormone treatment. She was given domperidone as a galactogogue for 1 month. The pumping protocol began with a double electric breast pump combined with manual pumping 6 months before her child was delivered, and 3 months later, she was accepted as a donor by our milk bank. This highlights the importance of regular stimulation as a milk production mechanism. This is the first case of human milk donation in an adoptive mother described in the literature.

Expressed Breast Milk Volume May Need to Be Considered in Studies of Lactational Programming of Obesity

There is increased interest in “lactational programming” as a potential mechanism by which maternal and offspring obesity are linked; that is, there are bioactive hormonal and other factors in milk that vary by maternal nutritional status and can alter infant growth rate. However, existing studies often do not consider whether breast milk sample volume could play a role in these associations.ObjectivesWe tested whether the volume of milk collected from mothers for hormone assays was associated with maternal pre‐pregnancy body mass index (BMI) and gestational weight gain. Secondary analyses examined the associations of breast milk volume with infant weight status.MethodsParticipants were 54 exclusively breastfeeding mother‐infant dyads (average maternal age 30.9 ± 3.8 years, 91% White), enrolled in the ongoing Mothers and Infants LinKed for Healthy Growth (MILK) study. Maternal and infant anthropometrics and breast milk volume were assessed at one and three months postpartum. Pre‐pregnancy BMI and gestational weight gain were calculated using first prenatal visit weight, measured height, and delivery weight. Infant weight and length were measured and converted to WHO Z‐scores. Milk volume was assessed by having mothers provide a single complete breast expression using an electric breast pump (Medela, Inc.) exactly two hours after feeding their infant until volitionally satisfied. Linear regression models examined associations of maternal pre‐pregnancy BMI and gestational weight gain with milk volume, after controlling for age, parity, education, and race. Milk volume was also examined as a predictor of infant weight and length status.ResultsAverage pre‐pregnancy BMI was 25.6 ± 4.7 kg/m2 (53.7% normal weight, 25.9% overweight, 20.4% obese), and mean gestational weight gain was 14.1 ± 5.2 kg. Breast milk volume increased from 68.4 ± 32.0 ml at one month postpartum to 70.3 ± 35.1 ml at three months. An inverse association was observed between pre‐pregnancy BMI and milk volume at three months only (β=−3.13, p=0.006). Gestational weight gain was not associated with milk volume at one or three months. We also found that milk volume at one month was positively associated with weight for‐age Z‐scores at one (β= 0.01, p=0.015) and three months (β= 0.01, p=0.023). Milk volume was not associated with length‐for‐age or weight‐for‐length Z‐scores.ConclusionsPreliminary analyses from the MILK study showed that greater pre‐pregnancy BMI was associated with a reduction in milk volume from a standardized milk expression at three months postpartum. Milk volumes were also positively associated with weight‐for‐age Z‐scores at one and three months postpartum. If milk hormone concentrations are found to vary with milk volume produced, our results indicate the need to control for this factor when examining the role of breast milk hormones in the transmission of obesity risk from mother to offspring.Support or Funding InformationR01 HD080444 (National Institute for Child Health and Development)

Hyperlactation Associated With Oral Contraception Use: A Case Report, Part 1

In this report, two women, whose infants were unable to transfer sufficient milk from the breast when solely breastfeeding, established and maintained their milk supplies using double electric breast pumps. After a delayed initiation of pumping, and without an infant influencing production, these women experienced hyperlactation. Milk storage soon became problematic. Each woman attempted to downregulate her supply by pumping less often for fewer minutes each time, yet both experienced increased production after their infants were 1 month old. This case report investigates why, with decreasing breast stimulus, their milk supplies increased. Commonality between these women was a shared history of long-term use of progestin-only birth control pills and/or injections, followed by infertility issues prior to getting pregnant. We’ve noted a potential association between hyperlactation and the long-term use of progestin-only birth control in two women. This information may be significant in our understanding of basic lactation physiology and potential external ramifications previously not researched.

Postdischarge Breastfeeding Outcomes of Infants With Complex Anomalies That Require Surgery

To examine the duration and exclusivity of breastfeeding and provision of human milk among infants with complex anomalies that require surgery postdischarge from a neonatal intensive care unit (NICU). Prospective cohort study. A tertiary care children's hospital with a fetal diagnostic and treatment center, special delivery unit, and NICU. Mothers who had delivered infants with complex anomalies that require surgery between 2009 and 2012 (N=165). Phone interviews were used for data collection and were analyzed using descriptive statistics methods. The average duration of breastfeeding/provision of human milk was 8 months. The percentage of infants who received human milk at 6 months was 60.1% (n=98/163,; p=.0063) and at 12 months was 34.5% (n=57/165, p=.023). Of infants in this cohort, the percentage of those infants exclusively receiving human milk was 54.3% (n=89/164, p=.0004) at 3 months of age and 35.6% (n=58/163, p<.0001) at age 6 months. Another clinically important finding is that 30.7% of the cohort required gavage feeds postdischarge from the NICU. Even for the most surgically complex infant/mother dyads, breastfeeding outcomes can improve significantly with a strong prenatal lactation program, nursing staff with specific breastfeeding education, and a hospital culture that values and supports breastfeeding and the provision of human milk. These findings support the use of hospital-grade electric breast pumps postdischarge for families of infants with complex anomalies that require surgery, as approximately one third of the cohort went home on tube feeds and their mothers continued to pump their breast milk at home.

Improving Human Milk and Breastfeeding Practices in the NICU

To determine if systematic implementation of the Spatz Ten Steps for Promoting and Protecting Breastfeeding for Vulnerable Infants (Ten Steps) would result in an improvement in the percentage of infants receiving mother's own milk (MOM) at initiation of feedings and at hospital discharge. Continuous quality improvement (QI) process. Urban, 82-bed, Level-III NICU. Very- low-birth-weight (VLBW) infants weighing fewer than 1500 grams. The Ten Step method was implemented during a 3-year period. Process measurements included percentage of VLBW infants receiving MOM at initiation of feeds, number of mothers of VLBW infants with hospital-grade electric breast pump at hospital discharge, and number of mothers of VLBW infants initiating pumping within 6 hours of delivery. Outcome measurements included percentage of VLBW infants with any human milk at discharge to home and parent satisfaction with nurses' support of mother's efforts to breastfeed. Balancing measurements included percentage of VLBW infants at less than the third percentile for growth on the Fenton growth chart at discharge and receiving pasteurized donor milk (PDM). Significant improvements were achieved in the percentages of mothers expressing their milk within 6 hours of delivery, infants receiving MOM at initiation of feeds, and mothers with a hospital-grade pump at discharge. Improvements in these processes resulted in increased parent satisfaction with nurses' support of breastfeeding and a 3.1-fold greater odds of the VLBW infant receiving MOM at discharge in 2013 compared to 2010 (odds ratio [OR]= 3.01, 95% confidence interval [CI] [1.75, 5.17], p<.001). Despite an increase in the use of MOM, there was not a significant increase in VLBW infants discharged at less than the third percentile for growth, and initiation of PDM did not negatively affect the percentage of VLBW infants with any human milk at discharge. Implementation of the Ten Steps method using QI methodology resulted in significantly improved rates of use of MOM at initiation of feeds and at hospital discharge.

Growth Patterns in Infants Fed Human Milk via a Bottle: A Case Report, Part 2

In this report, 2 women, whose infants were unable to transfer sufficient milk from the breast when solely breastfeeding, established and maintained their milk supplies using double electric breast pumps. After a delayed initiation of pumping, and without an infant influencing production, these women experienced hyperlactation. Milk storage soon became problematic. Each woman attempted to downregulate her supply by pumping less often for fewer minutes each time, yet both experienced increased production after their infants were 1 month old. This case report investigates why, with decreasing breast stimulus, their milk supplies increased. Commonality between these women was a shared history of long-term use of progestin-only birth control pills and/or injections, followed by infertility issues prior to getting pregnant. We’ve noted a potential association between hyperlactation and the long-term use of progestin-only birth control in two women. This information may be significant in our understanding of basic lactation physiology and potential external ramifications previously not researched.

EXPRESSION OF BREAST MILK AS THE WAY OF MAINTENANCE OF LACTATION

The necessity of maintenance of breast feeding of a child in the first months of his life causes the need for development of preventive measures and plugged duct treatment. Results of use of electric breast pumps by mothers under impossibility of breast feeding by a physiological way are presented. It is shown that modern breast pumps, optimally imitating a peristaltic sucking of a child, allow to reduce time for expression, and also to make it painless and comfortable. It supports mothers' desire of long breast feeding, providing, thus, formation of a child health.

Using mPINC data to measure breastfeeding support for hospital employees.

Employer support is important for mothers, as returning to work is a common reason for discontinuing breastfeeding. This article explores support available to breastfeeding employees of hospitals that provide maternity care. This study aimed to describe the prevalence of 7 different types of worksite support and changes in these supports available to breastfeeding employees at hospitals that provide maternity care from 2007 to 2011. Hospital data from the 2007, 2009, and 2011 Centers for Disease Control and Prevention Survey on Maternity Practices in Infant Nutrition and Care (mPINC) were analyzed. Survey respondents were asked if the hospital provides any of the following supports to hospital staff: (1) a designated room to express milk, (2) on-site child care, (3) an electric breast pump, (4) permission to use existing work breaks to express milk, (5) a breastfeeding support group, (6) lactation consultant/specialist available for consult, and (7) paid maternity leave other than accrued vacation or sick leave. This study was exempt from ethical approval because it was a secondary analysis of a publicly available dataset. Of the 7 worksite supports in hospitals measured, 6 increased and 1 decreased from 2007 to 2011. Across all survey years, more than 70% of hospitals provided supports for expressing breast milk, whereas less than 15% provided direct access to the breastfeeding child through on-site child care, and less than 35% offered paid maternity leave. Results differed by region and hospital size and type. In 2011, only 2% of maternity hospitals provided all 7 worksite supports; 40% provided 5 or more. The majority of maternity care hospitals (> 70%) offer breastfeeding supports that allow employees to express breast milk. Supports that provide direct access to the breastfeeding child, which would allow employees to breastfeed at the breast, and access to breastfeeding support groups are much less frequent than other supports, suggesting opportunities for improvement.

Randomized Trial Comparing the Effectiveness of 2 Electric Breast Pumps in the NICU

Mothers with preterm infants may need to express milk for considerable periods. Research to improve breast pump design has focused on compression stimuli, frequencies, and vacuums. This study aimed to compare the effectiveness of 2 electric pumps: Medela Symphony (pump S) and a novel pump (Philips AVENT Twin electronic pump; pump A). Both offer flexibility of rate and suction; pump A also incorporates petal compression cushions. Primary outcomes were (1) milk weight expressed during 10-day study period and (2) weight of milk expressed in a 15-minute test. Seventy-one mothers with preterm infants < 34 weeks were randomized. Mothers completed 10-day diaries including weight of milk expressed. Milk weight expressed during a single 15-minute test period and data on pumping mode, skin-to-skin contact, breastfeeding at infant discharge, and mothers' opinions of the pump were recorded. There was no significant difference in milk expressed during the first 10 days between groups. Pump S mothers expressed significantly more milk during a fixed 15-minute period. Mothers using pump A awarded higher scores for certain characteristics of the pump, notably location of control button and ease of use. Similar proportions of infants received breast milk at discharge, but pump A mothers were more likely to be directly breastfeeding (odds ratio, 4.27 [95% confidence interval, 1.29, 14.1]). The breast pumps showed similar effectiveness in terms of milk expression and maternal opinions. The finding that breast pump design may influence breastfeeding at infant discharge merits further investigation.

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

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. 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. 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. 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). 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.