(This article is a revised and updated version of an earlier article by the same author, which was originally published in a 2013 issue of Neonatal Intensive Care)
Human milk is recognized as the gold standard for infant nutrition. Expert opinion acclaims the many health benefits of human milk for healthy newborns and especially for infants born prematurely (AAP Section on Breastfeeding 2012). In the last decade, a plethora of research studies have substantiated the health benefits of human milk for premature infants. These studies have shown that mother’s milk provides protection from a host of prematurity-specific morbidities and their long term consequences. Mother’s milk has been designated a “medicine” that both nourishes and protects fragile premature infants (Meier 2007).
Unfortunately, prematurity does not always allow infants to feed at the breast. As a result, mothers find it necessary to employ breast expression techniques that allow them to provide sufficient volumes of breast milk for their infants. This provision of human milk requires a coordinated effort between mothers wishing to express their milk and the clinicians who provide care to them. Clinicians find it necessary to search for evidence-based technology and practices that will ensure mothers provide an adequate supply of human milk for their infants.
This post is written for all clinicians who work with pump dependent mothers. It is meant to provide a brief overview of best pumping practices that help to ensure pump-dependent mothers initiate, build and maintain adequate volumes of human milk for their premature infants.
Initiation of Milk Volumes: The Normal Process of Lactation
The lactation process originates during pregnancy, under the influence of a variety of hormones. This hormonally controlled process, referred to as Secretory Differentiation or Lactogenesis I, occurs irrespective of the mother’s decision to provide human milk for her infant after birth.
After the delivery of the placenta and the sudden decline in circulating progesterone, serum prolactin levels rise, resulting in an increase in maternal milk volume. Termed Secretory Activation or Lactogenesis II, this onset of copious milk production occurs normally between 36 and 96 hours after birth and occurs, again, irrespective of the mother’s decision to provide human milk for her infant.
After the onset of copious milk production, milk synthesis continues if milk is removed either by a healthy suckling infant or by mechanical expression. Involution of the milk secreting cells results, however, if milk is not removed. Milk stasis within the breasts occurs resulting in over-distention or engorgement. Repeated and effective milk expression after Secretory Activation will continue to drive milk synthesis.
What Happens if Infants are Born Prematurely?
However, pump-dependent mothers with premature infants appear to experience multiple lactation difficulties. This assumption is supported by numerous studies that indicate mothers of premature infants are at greater risk for delayed Secretory Activation and or low milk volume than mothers with healthy term infants (Meier 2007; Hill 1999, 2005; Cregan 2002; Hurst 2007).
Cregan’s work (2002) with preterm mothers concluded that many preterm mothers experience a compromised initiation of lactation resulting in low milk production in the early days post birth. Hill’s study (2005) demonstrated that pump-dependent mothers of premature infants were more likely to produce less milk in the early days post birth along with reduced milk volumes as they continued to express milk. Schanler and colleagues (2005) also witnessed pump dependent mothers struggle to maintain milk volumes for their premature infants.
Several risk factors have been identified that pose a risk for delayed. Secretory Activation (Hurst 2007; Hernandez 2009; Marshall 2010; Hilson 2004). Risk factors such as diabetes mellitus, preterm labor, pregnancy induced hypertension, excessive maternal blood loss, prolonged bed rest, maternal stress during labor and delivery, an unscheduled Cesarean delivery, obesity, and the use of selective serotonin re-uptake inhibitors (SSRIs) pose risks for any breastfeeding mother, but so commonly occur in mothers who give birth prematurely. Assessment for these lactation risk factors should be included when providing lactation support for mothers of premature infants.
Although insufficient volume of milk is commonplace among preterm mothers, Meier (2007, 2010) and Spatz (2004) contend that many occurrences may be avoided if mothers receive instruction and individualized care regarding best clinical practices during both the initiation phase (Secretory Activation) and maintenance phase of lactation. The following paragraphs describe these best practices. A quick reference list (Table 1) identifies these practices.
Initiation, Building and Maintaining Milk Volumes: Best Practices
The first two weeks post-birth represents a critical period in lactation for all breastfeeding mothers. Due to the complex endocrine, anatomic and biochemical changes occurring during this first two week period, breastfeeding needs to get off to a good start. For the healthy term breastfeeding baby, this requires frequent feeding at the breast in the range of 8 to 12 times per day. In the absence of a healthy term breastfeeding baby, the mother of a preterm infant is at risk for diminishing milk volume; her milk supply may decrease and be insufficient to meet the nutritional needs of her infant. Hill (2005) cites decreasing maternal milk volume as the reason many NICU mothers are unable to meet their lactation goals.
Getting Started: When and How
Studies indicate (Hill 2001; Furman 2002; Parker 2012, 2015) mothers of premature infants should initiate milk expression as soon as possible after delivery. Hill (2001) demonstrated correlation of early breast expression and milk volumes during 2-5 days postpartum. Furman (2002) demonstrated that mothers who initiated milk expression within 6 hours of delivery were more likely to continue lactation beyond 40 weeks. Spatz (2004) recommends mothers begin milk expression within the first 6-12 hours after birth. Parker’s studies (2011, 2015) of 20 mothers who delivered VLBW premature infants and began milk expression within 1 hour of delivery produced significantly more milk during the initial days after birth and during the entire six weeks of the study than mothers who initiated milk expression between 1 and 6 hours after delivery.
The use of a multi-user, evidence-based double electric breast pump has been recommended for pump dependent NICU mothers to help them achieve adequate volumes of breast milk (Spatz 2004; Hurst 2010; Academy of Breastfeeding Medicine, Clinical Protocol #12, 20014; CPQCC 2008; Meier 2016). Meier (2010) states, “A breast pump is fundamental to a mother’s ability to produce milk, and it is critical that NICU mothers receive the most effective, efficient, comfortable, and convenient breast pump available” (p 34). Mothers should be instructed to pump at the same frequency that duplicates the breastfeeding frequency of a healthy term infant. This frequency is required to drive continued milk production. The more milk is removed from the breast either by a healthy baby or by a breast pump, the more milk will be made. This is known as the supply and demand principle of continued lactation. Spatz (2004) and Rodriquez (2005) recommend mothers pump every 2 to 3 hours each day. Walker (2010) suggests pumping eight or more times in twenty-four hours. Participants in Parker’s studies (2011, 2015) were instructed to pump at least eight times in twenty-four hours.
Simultaneously pumping both breasts reduces the time mothers spend while pumping and has been reported to increase milk volumes. (Hill 2001; Prime 2012). Prime reported a higher caloric content of expressed milk and an additional milk ejection when mothers double pumped.
No research evidence exists to recommend how long an individual pumping session should last. It is frequently recommended that during the Initiation Phase of lactation, mothers should pump for approximately fifteen minutes. After the onset of Secretory Activation, mothers should be instructed to pump for two minutes after the last droplets are noted (Meier 2010). This ensures all available milk has been expressed and the high fat milk has been removed. A well-drained breast will more rapidly synthesize breast milk than a breast that is partially drained (Daly 1996). Kent (2008) recommends mothers pump using Maximum Comfort Vacuum™ (MCV), the highest yet comfortable vacuum setting of the pump while expressing milk. Research has demonstrated this allows a mother to pump more efficiently.
Hand expression has been mentioned to aid in the retrieval of the small quantities of colostrum produced during the initial stages of lactation. Morton (2009) demonstrated greater volumes of colostrum in mothers who performed hand expression 5 times a day combined with use of a double, electric breast pump more than five times a day in the first few days after birth. Ohyama (2010) found gentle manual expression during the first 48 hours was the best way to obtain small quantities of produced colostrum. Slusher (2007) however reported a decrease in milk volumes using hand expression compare to using an electric breast pump in the first several days post birth. Lussier’s study (2015) with mothers of VLBW infants demonstrated less cumulative daily milk production utilizing exclusive hand expression compared to exclusive use of an electric breast pump to express milk. The study authors suggested exclusive use of an electric breast pump was superior to hand expression alone in establishing a milk supply in pump dependent mothers.
A recent study by Meier (2011) demonstrated increased volumes of expressed milk when mothers utilized a breast pump suction pattern that mimicked the unique sucking action of the healthy term infant. Previously, Meier (2008) demonstrated hospital-grade electric breast pumps that mimic the biphasic sucking behavior of healthy infants during established breastfeeding are thought to be as effective and more comfortable than single-phase electric breast pumps.
The Medela (McHenry, IL) Symphony® PLUS™ Breast Pump with Initiation Technology™, that incorporates the sucking pattern utilized by healthy-term infants during the first few days after birth has been shown to improve initial milk volumes. In a randomized control trial of pump dependent mother of preterm infants, mothers produced an average of 43% more milk by day four and an average of 67% more milk by day seven. Increased milk volumes were maintained throughout the two week study with mothers pumping 124 fewer minutes during the trial. Similar results were found in other studies regardless of infants’ gestational age (Torowicz, 2015; Post 2016; Meier 2016).
Breast milk is undeniably the best nutrition for premature infants. The process of initiating and maintaining adequate volumes of breast milk to meet the nutritional needs of the premature infant requires dedication from mothers and a commitment on the part of bedside clinicians to teach, support and provide up to date evidence on best practices. Many mothers find the challenges of pumping milk for their premature infants overwhelming. They struggle with many issues and have to overcome many obstacles to be successful. Yet many mothers find the process of milk expression for their preterm infants rewarding and empowering.
Bedside clinicians can make a tremendous difference in the pumping experiences of pump dependent mothers challenged to provide expressed milk for their premature infants. Clinicians need to be knowledgeable about current best pumping practices and integrate them into the care they provide to pump dependent mothers.
Are you looking for more information on this subject? Read a previous post, Support Breastfeeding From Hospital to Home, featuring an infographic with the initiate, build and maintain stages to help clinicians and patients with the proper breast pump based on a mother’s lactation journey.
Learn more about Symphony® PLUS™, a multi-user, evidence-based double electric breast pump with research-based programs developed specifically to support mothers throughout their lactation journey: to initiate, build and maintain adequate milk production.
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