The recommended frequency of breast pump use for mothers of preterm and critically ill infants hospitalized in the newborn intensive care unit (NICU) has been a subject of debate for decades—and rightfully so. Until very recently, there has been no objective evidence to guide these recommendations. In the absence of data, the “let’s be on the safe side” approach has taken over, with instructions for mothers to pump at least 8-12 times during this critical interval. The rationale for these frequent pumpings has ranged from “it is consistent with the full-term healthy infant during breastfeeding” to the paternalistic strategy of telling a mother to pump a minimum of 8 times daily so that she will actually pump 6 times. These approaches are not personalized to the individual mother—especially with respect to common underlying maternal health complications in the immediate postpartum period—and are long overdue for revision using objective data. The recommendation for ≥ 5 daily pumpings within the My Pumping Pathways has evolved from recent research by our team [Dr.s Rebecca Hoban, Leslie Parker, Tricia Johnson] and others, and reflects the current state of the science.1
Pumping Frequency is Only One Component
A primary objective of My Pumping Pathways is to standardize breast pump use for breast pump-dependent mothers of NICU infants, assuring that each item in the pathways is addressed (e.g., standardization of practice), while also being personalized to the individual mother. A concept fundamental to My Pumping Pathways is that a mother may have a top-of-the line electric breast pump, but if it is not used appropriately, Mothers Own Milk (MOM) volume will not be optimized. As detailed in the Pumping Pathways and previous studies by our team, pumping frequency cannot be evaluated independent of pumping effectiveness, efficiency and comfort.2, 3 For example, a mother may have access to a Symphony Pump with Initiation™ technology, but if no one has helped her personalize pumping pressures, breast shield sizing, selected the appropriate pumping program or the use of simultaneous versus serial pumping, pumped MOM volume will not be optimized, regardless of pumping frequency. In other words, she may pump frequently, but ineffectively. Similarly, when a mother reports small pumped MOM volumes, she is commonly instructed to increase pumping frequency, typically without anyone watching her pump to assure appropriate breast pump use. All too often, infrequent pumping is cited as a catch-all reason for inadequate MOM volume when the primary cause may be lack of effectiveness, efficiency and comfort in breast pump use.
Why a Minimum of Five Times Daily?
In a review of studies for which pumped MOM volume was a primary dependent variable, we found that the overwhelming majority of researchers instructed mothers of preterm infants to pump either every 2-3 hours or a minimum of 8-12 times daily.4 However, only a handful of mothers met these recommendations, with the majority pumping between 3-5 times daily in the first postpartum days.4, 5 These findings suggest that the majority of breast pump-dependent mothers either do not or cannot comply with these frequency recommendations. A closer observation of studies linking pumping frequency to achievement of lactation milestones including secretory activation (SA; lactogenesis II, MOM coming in) and coming to volume (CTV; ≥ 500 mLs/day by postpartum day 14) have revealed that ≥ 5 daily pumpings in the first 5 postpartum days is highly associated with achievements of SA6 and CTV.6, 7 Similarly, in a study for which all pumping behaviors were measure electronically, thus eliminating errors with maternal report, we found that ≥ 5 daily pumpings, compared to ≤ 4 daily pumpings, was associated with greater pumped MOM volume and achievements of SA and CTV.4 Using these pumping frequency data to predict NICU-specific outcomes represents an important first step in leveraging evidence to inform pumping guidelines.
The Minimal Frequency is the Baseline, Not Necessarily the Optimal
The papers in our recent special edition of Breastfeeding Medicine shed light on the role of pumping frequency in the achievements of SA and CTV in breast pump-dependent mothers with preterm infants <34 weeks of gestation.1 In all studies, a dose-response relationship between pumping frequency and pumped MOM volume was reported for the first 14 postpartum days.8–10 In other words, ≥ 5 daily pumpings may predict achievements of SA and CTV, but more pumpings likely yield more pumped MOM volume in most, but not all, mothers. In a study of 29 breast pump-dependent mothers for whom all pumping frequency data were objective and automated, Medina Poeliniz reported that each additional hour spent pumping over the first five postpartum days yielded a cumulative additional 1,278 mLs by postpartum day 7.8 Johnson et al reported that pumped MOM volume, achievement of SA and maintenance of paracellular pathway closure through to postpartum day 14 were highly associated with pumping frequency in 66 mothers of preterm infants.9 In particular, both the Medina Poeliniz et al and the Johnson et al studies incorporated components of My Pumping Pathways to standardize effectiveness, efficiency and comfort of breast pump use, thus showcasing the role of pumping frequency. In these and previously-published studies, the “average” pumping frequency reflects a wide range of individual pumping behaviors, oftentimes from as few as 3 to as many as 9 daily pumpings. Thus, pumping frequency recommendations in My Pumping Pathways can be personalized to the mother, but should not be increased routinely just to “be on the safe side.”
Why Not Err on the Side of Increasing Pumping Frequency?
The breadth and severity of maternal health complications that are common among today’s mothers of NICU infants, especially those with preterm birth, has increased dramatically, with our recent research revealing an average of 3 co-morbidities per mother. Many complications, including overweight/obesity, hypertensive disorders of pregnancy, diabetes and strategies for their treatment (Cesarean delivery, prenatal bedrest, medications, etc.), are independently associated with decreased pumped MOM volume.10 In addition to health problems, these mothers are intensely stressed due to the NICU admission, in pain, and often unable to sleep. These symptoms blunt the impact of the pumping-induced prolactin response to mammary gland stimulation, so despite increased pumping frequency, increased MOM volume may not materialize.11 Thus, My Pumping Pathways does not include a recommendation to waken mothers during the night to achieve the daily pumpings because no evidence exists to inform this recommendation. Fortunately, the relationship among maternal sleep, co-morbidities of pregnancy and nighttime pumping in breast pump-dependent mothers of preterm infants is currently the focus of prospective research by Medina-Poeliniz, so definitive recommendations should be forthcoming.
Hoban et al. studied inter-pump interval in 29 mothers of preterm infants for which all pumping behaviors were recorded electronically. Whereas number of daily and cumulative pumping sessions predicted achievements of SA and CTV, the number of inter-pump intervals > 5 hours did not. Medina-Poeliniz reported a negative but non-significant relationship between inter-pump intervals > 5 hours in the first 5 days postpartum and MOM volume on day 7 postpartum. Although lengthy inter-pump intervals likely impact the autocrine/paracrine control of lactation, this mechanism regulates MOM synthesis and secretion after SA achievement, as . illustrated elegantly by Lai et al. In a study of 25 mothers of preterm infants enrolled on or after postpartum day 10, Lai et al found that short-term rate of MOM synthesis was negatively associated with inter-pump intervals > 7 hours. However, by 10 days postpartum, SA will have been achieved in the overwhelming majority of mothers, so these data cannot be generalized to mothers for whom the control of lactation is primarily hormonal (e.g., prior to SA achievement). Nonetheless, a commonsense recommendation for mothers is to pump if they waken during the night, especially if the waking is related to full or leaking breasts, signaling SA achievement. This guideline differs from telling a mother to set an alarm clock to pump on a nighttime schedule, which should be avoided in the absence of data that informs its appropriateness for this population.
Summary
In summary, it is not on the safe side to tell mothers of NICU infants to pump more frequently than necessary, given the fact that these mothers must balance pumping with sleep, rest and recovery. The minimum of > 5 daily pumpings during the early postpartum period is consistent with the evidence that links it to achievements of SA and CTV in this population. In particular, the critical takeaway message is to assure optimal breast pump usage, for which pumping frequency is only one component. My Pumping Pathways provide the guidelines to assure that breast pump-dependent mothers get the greatest advantage from the valuable time they spend pumping.
