Combining Hand Techniques With Electric Pumping Increases the Caloric Content of Milk in Mothers of Preterm Infants

J Morton; R J Wong; J Y Hall; W W Pang; C T Lai; J Lui; P E Hartmann; W D Rhine

Disclosures

J Perinatol. 2012;32(10):791-796. 

In This Article

Abstract and Introduction

Abstract

Objective: We previously reported that preterm mothers' milk production can exceed levels of term mothers by using early hand expression and hands-on pumping (HOP) with the highest production (955 ml per day) in frequent users of hand expression. In this study, we compared milk composition between mothers stratified by early hand expression frequency.
Study Design: A total of 67 mothers of infants <31 weeks gestation were instructed on hand expression and HOP. Subjects submitted expression records and 1-ml samples from each pumping session over 24 h once weekly for 8 weeks.
Result: 78% (52/67) of mothers completed the study. But for Week 1, no compositional differences (despite production differences) were noted between the three groups. Protein and lactose tracked reported norms, but fat and energy of mature milk (Weeks 2–8) exceeded norms, 62.5 g l−1 per fat and 892.7 cal l−1 (26.4 cal oz−1), respectively.
Conclusion: Mothers combining manual techniques with pumping express high levels of fat-rich, calorie-dense milk, unrelated to production differences.

Introduction

Although human milk is the preferred nutrition for premature infants, the major limitations have been inadequate supply[1,2] and suboptimal nutrients for the infant to achieve optimal growth.[3] More effective milk expression techniques may address both issues by removing a larger fraction of nutrient-dense 'hindmilk'.

We previously reported that mothers of preterm infants can attain and sustain high milk production levels by combining the use of electrical pumps with two manual techniques, hand expression and hands-on pumping (HOP) (Figure 1).[4] Mothers who initiated expression by using frequent hand expression (>5 × per day × 3 days) produced the highest subsequent volumes. The influence of hand expression in the first 3 days was independent of pumping frequency and affected production up to Week 8. We concluded that early hand expression may have removed viscous colostrum more effectively than pump suction alone, and thereby influenced the percentage of alveoli (milk secretory units) recruited for subsequent milk production.

Figure 1.

Mean daily volumes (MDV) of expressed milk over the course of the 8-week study of three groups as defined by frequency of hand expression during the first three postpartum days. Group I (<2 times per day, n=15), Group II (2 to 5 times per day, n=18) and Group III (>5 times per day, n=16) volumes are shown along with the output data of the Composite Group. Statistical comparisons using analysis of variance were performed only between Groups I, II and III. P<0.05 *vs Group I, vs Groups I and II. (Morton J, Hall JY, Wong RJ, Thairu L, Benitz WE and Rhine WD. Combining hand techniques with electric pumping increases milk production in mothers of preterm infants. J Perinatol 2009; 29: 757–764, reprinted with permission).

Once milk volume increased, all mothers received instruction on the second manual technique, HOP, at 20.6±9.6 days postpartum. This technique combines electric pumping with breast compression, massage, stripping and, if needed, hand expression. The use of HOP did not increase pumping time and was associated with longer uninterrupted sleeping time.[4]

This was the first report of mothers of preterm infants with a steady increase in production over 8 weeks, which surpassed reference levels for mothers of term infants. Recently, a pump with a newer suction pattern was shown to improve volume over earlier pumps, and yet subjects did not achieve production levels on a par with those we reported for mothers using frequent early hand expression. This pump was designed to mimic the suction pattern of the breastfeeding baby, but there is no feature to match the infant's oral compression and milking action.[5] We speculate that combining electric pumping with manual techniques (which include breast compression and a milking action) results in more effective breast emptying, thereby increasing milk production. If correct, one would expect compositional changes to include a higher percentage of hindmilk fat, possibly improving the nutritional adequacy of human milk for the preterm infant.

Milk fat, but not other macronutrients increases significantly in relation to breast emptying.[6] Special attributes of human milk fat for preterm infants have included the benefits of polyunsaturated fatty acids on neuronal development,[7] the superiority of absorption of human milk fat versus cow milk formula fat,[8] the improved caloric value of high fat feeding, and increased availability of fat-soluble vitamins.[9] Concerns about the nutritional inadequacies of human milk for the preterm infant have led to routine multi-nutrient fortification of human milk both pre- and post-discharge, with limited regard for compositional variation.[3] If expression techniques consistently and significantly affect the nutritional value, a more selective approach to fortification may be appropriate.

Currently, reports on the composition of milk of mothers of preterm infants and donor milk are primarily based on samples expressed using passive pump suction.[9,10,11] A possible influence of breast massage on milk composition was proposed by Foda et al.,[12] who reported total solids, lipids, casein and gross energy increase in milk hand expressed after using a Japanese method of breast massage.

The composition of milk expressed by combining pump suction with manual techniques has not previously been reported. Our objective was to investigate the constituents of milk in mothers using two techniques, which influence production (early hand expression of colostrum and HOP of mature milk). Furthermore, we compare milk composition in high production mothers (those initiating expression using hand expression >5 × day) to that in lower production mothers (those initiating expression using hand expression <2 × day, yet pumped with the same frequency).

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