Evaluation of Methods of Breast or Bottle Feeding on Length of Hospitalization of Preterm Infants

Abstract

Background:

Direct breastfeeding is the optimal method of nourishing preterm infants. Preconceived notions exist among health practitioners that establishment of direct breastfeeding lengthens hospitalization. Thus far, the aforementioned association remains unknown.

Research Aim:

The objective of this study was to assess the impact of direct breastfeeding establishment on length of hospital stay in preterm infants.

Methods:

A retrospective chart review on a sample of 101 mother–infant dyads was conducted in the neonatal intensive care unit at Kingston Health Sciences Center (KHSC) in Ontario, Canada. The sample consisted of three groups: (1) modified direct breastfeeding group, defined as infants receiving ≥50% direct breastfeeds during hospitalization, (2) partial breastfeeding group, defined as infants receiving <50% breastfeeds during hospitalization, and (3) bottle feeding group, defined as infants only receiving bottle feeds during hospitalization. A multiple linear regression model was performed to assess the relationship between length of hospitalization and method of oral feeds (modified direct breastfeeds vs. partial breastfeeds vs. bottle feeds) while controlling for infant (gestational age [GA], birth weight, 5 minutes Apgar score, ventilator support) and maternal (age, first-time mother, mental health conditions) factors.

Results:

GA was inversely associated with length of hospitalization. The number of days on ventilator support was positively associated with length of hospitalization. Method of oral feed, birth weight, 5 minutes Apgar score, maternal age, first-time mother status, and maternal mental health conditions were not associated with duration of hospitalization.

Conclusions:

Direct breastfeeding establishment does not lengthen hospitalization in preterm infants. This finding may aid health practitioners in increasing direct breastfeeding success in this population.

Background

Breast milk provides an optimal source of nutrients and immune protection for preterm infants.¹ As compared with formula, breast milk has been shown to decrease the risk of prematurity-associated complications, such as necrotizing enterocolitis and sepsis.² Despite these benefits, the rate of breastfeeding in mothers of preterm infants is low.³ In one study of 7,000 preterm infants, only 6% received direct breastfeeding at hospital discharge, and only 42% received human milk.⁴

To date, much of the research has been focused on the provision of mother's own milk in any form.^5,6 However, direct breastfeeding is preferable to expressed mother's milk. Mothers who breastfeed directly have increased breastfeeding duration, which enhances the likelihood of meeting the World Health Organization (WHO) recommendation for breastfeeding until 6 months of age.^6,7 The interplay of infant, maternal, and environmental factors serve as barriers to direct breastfeeding in preterm infants.⁸ Many infants born at <33 weeks gestational age (GA) cannot coordinate the sucking/swallowing/breathing process required for safe oral feeding.^8,9 The mother's milk volume may be insufficient to meet the demands of a preterm infant.⁸ Preterm infants require more calories per kilogram than term infants.⁸ Additional calories may be provided by fortified bottle feeds, which can interfere with the establishment of direct breastfeeding.⁸ The physical separation of the mother–infant dyad prevents bonding needed for direct breastfeeding establishment.⁸

Preconceived notions exist among health practitioners that direct breastfeeding establishment prolongs the transition from tube to full oral feeds, resulting in lengthened hospitalization.¹⁰ Hence, neonatal intensive care unit (NICU) staff appear to encourage bottle feeding over breastfeeding.⁶ However, the effect of direct breastfeeding establishment on duration of hospitalization in preterm infants remains unknown.¹⁰ To improve direct breastfeeding rates, a greater understanding of its impact on hospital stay is needed. The objective of this study is to compare the effect of direct breastfeeding on length of hospital stay in preterm infants.

Materials and Methods

Design and setting

This study is a retrospective chart review of preterm infants and their mothers admitted between January 2016 and March 2018 to the Kingston Health Sciences Center (KHSC) level II and III NICU—a tertiary care center in Ontario, Canada. KHSC is striving to become accredited under the Baby-Friendly Hospital Initiative (BFHI), a WHO-supported global effort to support breastfeeding initiation and exclusive breastfeeding until 6 months. The NICU is an open bay unit with a maximum capacity of 26 beds. Two KHSC NICU nurses are certified lactation consultants and are consulted when breastfeeding difficulties arise. The unit uses a cue-based feeding approach for the initiation and advancement of oral feeds. This is decided during daily medical rounds by the health care team, composed of nurses, dietitians, and neonatologists. Ethics approval for this study was obtained from the Queen's University Health Sciences Research Ethics Board.

Sample

The study sample consisted of 101 infants born less than 33 weeks of gestation. Infants born with genetic syndromes, congenital anomalies, or who were transferred to another facility were excluded. The study sample was divided into three groups. The first group included infants receiving ≥50% of their oral feeds directly from the breast from the start of oral feeds until hospital discharge, and are referred to as the modified direct breastfeeding group. This term was selected to allow for those infants who require supplementation with human milk fortifiers through bottle to maintain adequate growth. Infants in this group only received human milk, including donor human milk (DHM) and/or mother's own milk, throughout their hospitalization. The second group included infants receiving <50% of their oral feeds from the breast, and are referred to as the partial breastfeeding group. Infants in this group received human milk, in the form of DHM and/or mother's own milk, and formula throughout their hospitalization. The third group included infants receiving only bottle feeds, and are referred to as the bottle feeding group. Infants in this group only received formula throughout their hospitalization.

Measurements

The outcomes measured included attainment of full oral feeds (days) and length of hospitalization (days). This study defined attainment of full oral feeds as the first day on which infants were able to take the entire prescribed volume of nutrients by mouth for two consecutive days. The method (breast or bottle) and composition (formula or human milk) of each oral feed from the start of oral feeds to hospital discharge were recorded.

Several infant-related factors were documented, including GA, birth weight, gender, twin, Apgar scores at 5 minutes, neonatal morbidities, including intraventricular hemorrhage grades I–IV, severe bronchopulmonary dysplasia, Bell Stage >2 necrotizing enterocolitis,¹¹ number of days on mechanical ventilator support, and number of days on continuous positive airway pressure. These baseline factors were considered because they may influence an infant's ability to feed orally and prolong length of hospital stay.^9,12,13 Several maternal factors were also documented, including maternal age, marital status, first-time mother status, and medical history of mental health conditions, including anxiety and/or depression. These maternal factors were monitored because of their potential influence on breastfeeding.⁵ Data were obtained from both the mother's and infant's electronic medical records.

Statistical analyses

A one-way ANOVA and chi-square test were used to compare baseline infant and maternal factors between modified direct breastfeeding, partial breastfeeding, and bottle feeding groups, for continuous and categorical variables, respectively. A multiple linear regression model was performed to assess the relationship between length of hospital stay and method of oral feeds while controlling for covariates. Length of hospital stay was used as the dependent variable and method of oral feeds (modified direct breastfeeding, partial breastfeeding, and bottle feeding), GA, birth weight, Apgar score at 5 minutes, number of days on ventilator support, maternal age, first-time mother status, and maternal mental health conditions were used as independent variables. Infant and maternal factors were selected based on a scientific review of the literature, which identified these factors as potential contributors to infants' oral feeding performance.^5,9,12,13 SPSS version 27.0 was used to complete statistical analyses. Significance was set at p < 0.05.

Results

A total of 101 infants met the initial eligibility criteria. Of the 101 participants, 42 infants were included in the modified direct breastfeeding group, 39 infants were included in the partial breastfeeding group, and 20 infants were included in the bottle feeding group.

A summary of infant and maternal baseline characteristics can be found in Table 1. Assessment of continuous and categorical variables revealed that only first-time mother status was significantly different between the three groups (p = 0.009). The modified direct breastfeeding group had a greater percentage of first-time mothers (71%) compared with that of partial breastfeeding (33%) and bottle feeding groups (35%). There was no significant difference in the time to transition from tube to full oral feeds (p = 0.557) and length of hospitalization (p = 0.314) between the three study groups.

Table 1.

Summary of Infant and Maternal Baseline Characteristics

	Bottle feeding, n = 20	Partial breastfeeding, n = 39	Modified direct breastfeeding, n = 42	p
Infant characteristics
GA, weeks	31 ± 2.0 (27–33)	31 ± 2.5 (26–33)	32 ± 2.3 (27–33)	0.599
Birth weight, g	1,675 ± 450 (935–2,395)	1,595 ± 462 (830–1,665)	1,893 ± 608 (1,150–2,115)	0.526
Apgar scores, 5 minutes	7 ± 2.1	7 ± 2.1	8 ± 1.2	0.721
Infant illness, n (%)
IVH	3 (15)	3 (7)	2 (5)	0.395
BPD	5 (25)	3 (7)	3 (7)	0.611
NEC	0 (0)	2 (5)	2 (5)	0.398
Feeding issues	7 (0)	2 (5)	6 (14)	0.372
Respiratory support
Days on ventilator	2.1 ± 4.0	2.6 ± 7.2	1.0 ± 4.0	0.555
Days on CPAP	4.9 ± 5.8	5.9 ± 14.8	4.6 ± 9.0	0.512
Discharge DOL	45.1 ± 22	45.9 ± 23	44.4 ± 27.3	0.314
Feeding characteristics
Number of days NPO	2.2 ± 2.3	3.8 ± 2.8	1.7 ± 2.9	0.514
Oral feeds
DOL first oral feed	22.2 ± 16.9	27.7 ± 25.1	29.2 ± 14.5	0.552
PMA first oral feed	34.2 ± 1.2	34.9 ± 2.1	34.2 ± 1.3	0.341
DOL full oral feeds	37.1 ± 18.1	41.9 ± 26.6	41.6 ± 16.7	0.741
PMA full oral feeds	36.6 ± 1.2	36.9 ± 2.2	36.3 ± 1.1	0.449
No. of days full oral feeds	14.9 ± 5.3	14.1 ± 5.1	12.4 ± 5.1	0.557
Maternal characteristics
Maternal age, years	27.2 ± 6.6	24.6 ± 4.3	30.1 ± 6.1	0.134
Multiples, n (%)	1 (5)	5 (13)	7 (17)	0.291
Anxiety or depression, n (%)	9 (45)	11 (28)	10 (24)	0.785
First-time mother, n (%)	7 (35)	13 (33)	30 (71)	0.009^*
Opioid use, n (%)	3 (15)	2 (5)	2 (5)	0.349

Data presented as mean ± standard deviation or frequencies, one-way ANOVA or chi-square test;^*p < 0.05. Feeding issues refer to infants who had enteral feeds stopped during their hospitalization.

BPD, bronchopulmonary dysplasia; CPAP, continuous positive airway pressure; DOL, day of life; GA, gestational age; IVH, intraventricular hemorrhage; NEC, necrotizing enterocolitis; NPO, nothing by mouth; PMA, postmenstrual age.

The multiple linear regression model revealed that GA was inversely related with length of hospital stay (p < 0.001) and number of days on ventilator support was positively associated with length of hospital stay (p = 0.008). The following variables were not associated with length of hospital stay: method of feed (p = 0.231), Apgar scores at 5 minutes (p = 0.761), maternal age (p = 0.516), first-time mother status (p = 0.261), maternal mental health conditions (p = 0.969), and birth weight (p = 0.451). A summary of the multiple linear regression model results can be found in Table 2.

Table 2.

Factors Associated with Length of Hospital Stay

	Unstandardized B	Coefficients standard error	Standardized coefficients beta	T	p
Constant	269.148	39.863		6.752	0.000
Oral feed method	−3.410	2.809	−0.116	−1.214	0.231
First-time mother	4.723	4.149	0.105	1.138	0.261
Apgar 5 minutes	0.314	1.026	0.026	0.306	0.761
Maternal age	−0.213	0.326	−0.055	−0.655	0.516
Mental health conditions	−0.163	4.136	−0.004	−0.040	0.969
GA	−6.823	1.579	−0.625	−4.321	0.000
BW	−0.006	0.008	−0.106	−0.747	0.451
Ventilator support	1.586	0.570	0.247	2.784	0.008

Bold text represents significant p < 0.05.

Dependent variable: length of stay, p multiple linear regression summary.

BW, birth weight; GA, gestational age.

Discussion

Establishing breastfeeding to meet the recommended health standards is an important public health issue for preterm infants. Among the infant and maternal barriers to successful direct breastfeeding, NICU staff misconception that bottle feeding leads to earlier hospital discharge may also be a contributor to the low direct breastfeeding rates in preterm infants. This study reveals that modified direct breastfeeding establishment does not prolong the length of hospitalization in preterm infants. These results along with findings from other researchers that examined breastfeeding at hospital discharge support the importance of promoting direct breastfeeding within the NICU.^6,10,14

The rate of direct breastfeeding observed in this study exceeds breastfeeding rates observed in previous research.⁴ A recent study by Hallowell et al. on 7,000 preterm infants revealed that 6% of preterm infants received direct breastfeeding at hospital discharge, and only 42% received human milk.⁴ The discrepancy in direct breastfeeding rates is due to this study's definition of direct breastfeeding as ≥50% direct breastfeeds throughout hospitalization. This definition was chosen to account for infants who require supplementation with human milk fortifiers, which can only be provided by bottle feeds. To account for this discrepancy, infants receiving ≥50% of their feeds by breast were referred to as the modified direct breastfeeding group, with the term “modified” reflecting supplementation by bottle.

In this study, GA and number of days on mechanical ventilator support were the only infant factors found to be associated with length of hospital stay. These findings are in keeping with previous research indicating that duration of hospitalization and number of days on mechanical ventilation is inversely correlated with GA at birth.^6,11,13,15 GA as well as the need for respiratory support is reflective of an infant's functional maturity, which is used to determine if an infant can be safely discharged from hospital. Hospital discharge readiness is typically determined by the achievement of competencies, including: body temperature regulation while in an open crib, respiratory stability, achievement of full oral feeds, and adequate weight gain.^16,17 Achievement of these milestones is inversely related to GA.^11,15,16 Moreover, the prevalence of prematurity-associated morbidities, such as sepsis, necrotizing enterocolitis, retinopathy of prematurity, and bronchopulmonary dysplasia is also inversely proportional to GA, which further prolong achievement of these hospital discharge milestones.¹⁶ In this study, the method of oral feeding did not influence length of hospital stay, but rather the infant's functional maturity as reflected by GA was the strongest predictive factor associated with the length of hospital stay. Thus, NICU health practitioners should not focus on method of feeding, but rather on the functional maturity of the preterm infant if the goal is to facilitate hospital discharge readiness. Research studies, including our own, have shown that early intervention strategies aimed at improving the oral motor skills associated with direct breastfeeding in preterm infants enhances achievement of full oral feeds.^11,18

In this study, maternal factors, specifically maternal age, first-time mother status, and mental health conditions were not associated with length of hospital stay. This finding is reflective of current practice wherein the decision to discharge an infant from the NICU is largely based on the infant's functional maturity rather than maternal characteristics.¹⁶ However, this study does reveal a significant difference among the modified direct breastfeeding group compared with partial breastfeeding and bottle feeding groups wherein first-time mothers were more likely to establish direct breastfeeding before hospital discharge. This study also revealed a trend toward increased breastfeeding rates in older mothers. These findings are supportive of previous research, which have found that maternal age is positively associated with direct breastfeeding in preterm and term infants.^3,19 One reason for this could be that maternal age is positively correlated with higher education and socioeconomic status, two other contributors to direct breastfeeding attainment.²⁰ These findings bring to light the importance for NICU health practitioners to attend to maternal factors as well as the infant when introducing oral feeds, and ensure that adequate resources are in place to enhance direct breastfeeding success for all mothers.

This study has the potential to aid in the development of educational interventions for NICU staff and mothers of preterm infants regarding the benefits of direct breastfeeding. Educational tools may aid in changing widespread attitudes about transition times and length of hospital stay as a result of feeding method. With proper education, there is hope that increased support from hospital staff will result in increased direct breastfeeding rates in the NICU.²¹ A retrospective chart review of 46 preterm infants found that mothers who were encouraged to have ≥1 direct breastfeeding session per day in the NICU were more likely to sustain breastfeeding after discharge.¹⁹ Similarly, a retrospective cohort study found that NICU mothers who received NICU-specific breastfeeding education were more likely to continue breastfeeding their infants at 1 and 3 months of age, with breastfeeding rates in this group superseding the national average breastfeeding rate at the 1- and 3-month benchmarks.²² Highlighting the importance of breastfeeding through education will likely improve infant outcomes without impacting transition from tube to oral feeds and length of hospital stay.

Potential study limitations include the retrospective nature of the study design, which limited data collection to information available in medical records. This made it difficult to cross-reference possible errors in documentation. Moreover, the study provided results from one NICU which may limit generalizability. Although a trend toward increased hospital stay in the modified direct breastfeeding group was not observed, it may have been difficult to appreciate a statistically significant difference between groups due to the small sample size. A larger prospective national cohort study following infants from hospitalization until 6 months corrected age is needed to confirm these results and to develop future interventions to increase and support direct breastfeeding establishment of preterm infants while in the NICU.

Conclusions

In conclusion, this study reveals that the method of oral feed, bottle, or breast, is not associated with length of hospital stay in preterm infants. Early interventions focused on maternal education and support are important strategies that health practitioners can facilitate to enhance direct breastfeeding success in preterm infants.

Footnotes

Authors' Contributions

Dr. Fucile conceptualized and designed the study, coordinated and supervised data collection, carried out the initial analyses, and reviewed and revised the article. Dr. Dow conceptualized and designed the study and reviewed and revised the article. Ms. Wener collected and organized the data, drafted the initial article and reviewed and revised the article. All authors approved the final article as submitted and agree to be accountable for all aspects of the work.

Acknowledgment

The authors would like to thank Lara Casey for her efforts in the database creation and collection phase.

Disclosure Statement

No competing financial interests exist.

Funding Information

No funding was received for this article.

References

Underwood

. Human milk for the premature infant. Pediatr Clin North Am, 2013; 60:189–207.

Groh-Wargo

, Thompson

. Managing the human-milk-fed, preterm, VLBW infant at NICU discharge: The sprinkles dilemma. Infant Child Adolesc Nutr, 2014; 6:262–269.

Hackman

, Alligood-Percoco

, Martin

, et al. Reduced breastfeeding rates in firstborn late preterm and early term infants. Breastfeed Med, 2016; 11:119–125.

Hallowell

, Rogowski

, Spatz

, et al. Factors associated with infant feeding of human milk at discharge from neonatal intensive care: Cross-sectional analysis of nurse survey and infant outcomes data. Int J Nurs Stud, 2016; 53:190–203.

Briere

, McGrath

, Cong

, et al. An integrative review of factors that influence breastfeeding duration for premature infants after NICU hospitalization. J Obstet Gynecol Neonatal Nurs, 2014; 43:272–281.

Pineda

. Direct breast-feeding in the neonatal intensive care unit: Is it important?. J Perinatol, 2011; 31:540–545.

World Health Organization (WHO). Report of the Expert Consultation on the Optimal Duration of Exclusive Breastfeeding. Geneva, Switzerland: World Health Organization, 2001.

Lau

. Breastfeeding challenges and the preterm mother-infant dyad: A conceptual model. Breastfeed Med, 2018; 13:8–17.

Mizuno

, Ueda

. The maturation and coordination of sucking, swallowing, and respiration in preterm infants. J Pediatr, 2003; 142:36–40.

10.

Briere

, Gephart

. Breastfed or bottle-fed: Who goes home sooner?. Adv Neonatal Care, 2015; 15:65–69.

11.

Hintz

, Bann

, Ambalavanan

, et al. Predicting time to hospital discharge for extremely preterm infants. Pediatrics, 2010; 125:e146–e154.

12.

Sakalidis

, Geddes

. Suck-swallow-breathe dynamics in breastfed infants. J Hum Lact, 2016; 32:201–211.

13.

Selley

, Ellis

, Flack

, et al. Coordination of sucking, swallowing and breathing in the newborn: Its relationship to infant feeding and normal development. Br J Disord Commun, 1990; 25:311–327.

14.

Smith

, Durkin

, Hinton

, et al. Initiation of breastfeeding among mothers of very low birth weight infants. Pediatrics 2003;111;1337–1342.

15.

Rawlings

, Scott

. Postconceptional age of surviving preterm low-birth-weight infants at hospital discharge. Arch Pediatr Adolesc Med, 1996; 150:260–262.

16.

Jefferies

, Canadian Paediatric

Society

, Fetus and Newborn

Committee

. Going home: Facilitating discharge of the preterm infant. Paediatr Child Health, 2014; 19:31–36.

17.

Smith

, Hwang

, Dukhovny

, et al. Neonatal intensive care unit discharge preparation, family readiness and infant outcomes: Connecting the dots. J Perinatol, 2013; 33:415–421.

18.

Lessen

. Effect of the premature infant oral motor interventions on feeding progression and length of stay in preterm infants. Adv Neonatal Care, 2011; 11:129–139.

19.

Briere

, McGrath

, Cong

, et al. Direct-breastfeeding in the neonatal intensive care unit and breastfeeding duration for premature infants. Appl Nurs Res, 2016; 32:47–51.

20.

Herich

, Cuttini

, Croci

, et al. Maternal education is associated with disparities in breastfeeding at time of discharge but not at initiation of enteral feeding in the neonatal intensive care unit. J Pediatr 2017;182:59–65.e7.

21.

Folker-Maglaya

, Pylman

, Couch

, et al. Implementing a breastfeeding toolkit for nursing education. J Perinat Neonatal Nurs, 2018; 32:153–163.

22.

Shapiro

, Rios

, Bogdanffy

, et al. The effect of breastfeeding education in the NICU on post-discharge breastfeeding duration. Pediatrics, 2017; 140:10.