Patterns and Predictors of Donor Human Milk Non-consent in the Neonatal ICU

Abstract

Background:

Previous research has not evaluated predictors of donor human milk (DHM) non-consent status in a neonatal intensive care unit (ICU) setting within the United States. The purpose of this study is to identify and describe maternal and infant factors associated with DHM consent status in a Level IV inner-city neonatal ICU.

Materials and Methods:

Demographics and additional maternal/infant data were stratified by DHM consent and compared with the appropriate parametric/nonparametric hypothesis testing statistic. A predictive multivariable logistic regression model was constructed, adjusted for independent predictors identified in the bivariate analysis (p≤0.2) using a backwards selection process (retention threshold p≤0.1). The adjusted odds ratios generated from the multivariable model identified predictors independently associated with DHM non-consent.

Results:

Data were analyzed for 113 mother–infant dyads from the first 18 months of a DHM program, with 65 mothers consenting to DHM and 48 not consenting. Race, ethnicity, marital status, education, delivery mode, and presence of a breastfeeding duration goal qualified for inclusion into the multivariable model. Only race and marital status were retained in the final model. In this sample, black race, other race, and being married are all independent predictors for DHM non-consent.

Conclusions:

Black race, other race, and marital status statistically predicted DHM non-consent in a Level IV inner-city neonatal ICU. These results are relevant to all neonatal ICUs who use DHM and to those who are developing DHM programs.

Introduction

The health benefits of pasteurized banked donor human milk (DHM) for very low birth weight (≤1,500-g) infants are known.^1–5 Use of DHM in the neonatal intensive care unit (ICU) permits very low birth weight infants to receive some of the advantages of human milk when mother's own milk may not be available.^3,6 The Surgeon General's 2010 Call to Action to Support Breastfeeding emphasized the value of DHM,⁷ while the World Health Organization and the American Academy of Pediatrics recommend that preterm infants receive DHM if mother's own milk is unavailable.^8,9 Recent findings suggest an exclusively human milk-based diet is associated with significantly lower rates of necrotizing enterocolitis and surgical necrotizing enterocolitis.^1,3 Consequently, many neonatal ICUs in the United States offer DHM as a supplement to mother's own milk in order to provide human milk as a preferred alternative to formula for the VLBW population.^10,11

The concept of using DHM has been explored in various international settings, demonstrating that DHM consent rates are dependent on maternal education or cultural context.^12–14 However, previous research has not evaluated predictors of DHM non-consent status in a neonatal ICU setting within the United States. The purpose of this study is to identify and describe maternal and infant factors associated with DHM consent status in a Level IV inner-city neonatal ICU. We also describe specific reasons for DHM non-consent.

Materials and Methods

Setting

In August 2010, DHM became regularly available for use as a first alternative to mother's own milk at Connecticut Children's Medical Center's Level IV, inner-city Hartford neonatal ICU. Infants born at ≤32 weeks of gestation or ≤1,800 g are eligible to receive DHM for 10 weeks or until the infant achieves 50% full oral feedings. Parental consent is sought once and is obtained prior to providing DHM. Non-consenters were not subsequently approached about DHM use. Infants born at the hospital in Hartford who qualified for DHM use from August 1, 2010 through December 31, 2011 (n=113) were included in these analyses. In-hospital medical records were used for this retrospective cohort study.

Statistical analyses

Demographics and additional maternal/infant data were stratified by DHM consent and compared with the appropriate parametric/nonparametric hypothesis testing statistic (chi-squared/Fisher's exact test for categorical variables and t test/Wilcoxon Mann–Whitney test for continuous variables). A multivariable logistic regression model adjusted potential predictors identified in the bivariate analysis (p≤0.2) using a backwards selection process (retention threshold p≤0.1). The adjusted odds ratios generated from the multivariable model identified predictors independently associated with DHM non-consent.

This research was exploratory, and no sample size calculation was conducted. Analyses were performed with SAS version 9.3 software (SAS Institute, Inc., Cary, NC). All p values were two-sided, and significance was set at α<0.05. The Connecticut Children's Medical Center Institutional Review Board approved this study.

Results

Sample characteristics were stratified by DHM consent status (Table 1). By DHM consent status, the 113 infants that qualified for inclusion to this study did not statistically differ by ethnicity, multiple births, parity, insurance type, partner support, education level, maternal history of obesity, maternal history of infertility, maternal history of polycystic ovarian syndrome, maternal history of breastfeeding, delivery mode, gestational age, infant death in the neonatal ICU, or infant diagnosis of necrotizing enterocolitis or sepsis. The distribution of maternal race, presence of a breastfeeding duration goal, and marital status differed significantly by DHM consent status (Table 1).

Table 1.

Study Cohort Characteristics

	Donor human milk consent
	No (n=48)		Yes (n=65)
Variable	n	%	n	%	p value
Race^a					0.02
White	18	40.0	39	63.9
Black	17	37.8	18	29.5
Other	10	22.2	4	6.6
Ethnicity					0.20
Hispanic	9	18.7	46	70.8
Non-Hispanic	39	81.3	19	29.2
Multiple birth					0.52
Yes	8	16.7	14	21.5
No	40	83.3	51	78.5
Parity					0.26
Primiparous	28	58.3	31	47.7
Multiparous	20	41.7	34	52.3
Insurance type^a					0.74
State	25	53.2	31	50.0
Private	22	46.8	31	50.0
Married					0.05
Yes	31	64.6	30	46.2
No	17	35.4	35	53.8
Partner support^a					0.41
Yes	42	91.3	56	86.1
No	4	8.7	9	13.9
Education^a					0.17
< High school	1	2.56	7	13.7
High school graduate	11	28.2	15	29.4
> High school	27	69.2	29	56.9
Maternal history of obesity^a					0.46
Yes	6	13.9	6	9.4
No	37	86.1	58	90.6
Maternal history of infertility^a					0.87
Yes	8	19.0	11	17.7
No	34	81.0	51	82.3
Maternal history of polycystic ovarian syndrome^a					0.99^†
Yes	4	8.9	5	7.9
No	41	91.1	58	92.1
Maternal history of breastfeeding^a					0.53
Yes	14	29.8	21	35.6
No	33	70.2	38	64.4
Delivery mode					0.11
Cesarean section	32	66.7	52	80.0
Vaginal	16	33.3	13	20.0
Breastfeeding duration goal^a					0.03
Yes	37	90.2	40	72.7
No	4	9.8	15	27.3
Necrotizing enterocolitis^a					0.69^b
Yes	4	8.3	3	4.9
No	44	91.7	58	95.1
Sepsis^a					0.41
Yes	8	17.0	7	11.5
No	39	83.0	54	88.5
Death prior to discharge					0.99^b
Yes	1	2.1	2	3.1
No	47	97.9	63	96.9
Reasons for donor human milk non-consent					—
All oral feeds, infant ineligible	4	8.3	—	—
Did not want someone else's milk	11	22.9	—	—
Father refused	2	4.2	—	—
Adequate mother's own milk production	4	8.3	—	—
Unknown	27	56.3	—	—
Provider obtaining consent					—
MD	—	—	25	38.5
APRN	—	—	24	36.9
IBCLC	—	—	15	23.1
RN	—	—	1	1.5

	Mean	SD	Mean	SD
Gestational age (weeks)	30.8	3.2	29.7	3.1	0.06^c
Maternal age (years)	30.4	6.0	30.8	8.0	0.75^c

Observations <113.

p value generated from a Fisher's test instead of a chi-squared test.

p values generated from a t test.

APRN, advanced practice registered nurse; IBCLC, International Board Certified Lactation Consultant.

Documented reasons for DHM non-consent included changing eligibility status, not wanting to use someone else's milk, father's refusal, and adequate mother's own milk production (Table 1). The majority of providers obtaining DHM consent were neonatologists or advanced practice registered nurses (Table 1). The day of life on which consent was obtained ranged from 0 to 64 (median, 1.0; interquartile range, 1.0–2.0).

Several factors identified in the bivariate analyses qualified for inclusion into the multivariable model (p≤0.2): race, ethnicity, marital status, education, delivery mode, and presence of a breastfeeding duration goal. The final model is presented in Table 2. Adjusted odds ratios >1.0 represent increased odds of DHM non-consent. Only maternal race and marital status were retained in the model. Black race, other race, and being married significantly predicted DHM non-consent status. The area under the final model's receiver operating characteristic curve was 0.69, indicating good discriminating power. The Hosmer and Lemeshow goodness-of-fit test was not statistically significant (p=0.95), suggesting the data fit the model sufficiently.

Table 2.

Independent Predictors of Donor Human Milk Non-consent

	OR (95% CI) (n=106)	p value^a
Race		0.005
White	1.00 (reference)
Black	3.77 (1.33–10.72)
Other	7.67 (1.90–31.0)
Married		0.007
Yes	3.85 (1.44–10.31)
No	1.00 (reference)

Represents the Type 3 analysis of effects Wald chi-squared p value.

CI, confidence interval; OR, odds ratio.

Discussion

Using data from the first 18 months of a DHM program, we identified independent predictors of DHM non-consent. In this cohort, the distributions of the numerous maternal and infant factors evaluated were similar in the consent and non-consent groups, with the result that few factors qualified for inclusion into the multivariable model (i.e., race, ethnicity, marital status, education, delivery mode, and presence of a breastfeeding duration goal). Only race and marital status were retained in the final model. In this sample drawn from a Level IV inner-city neonatal ICU, black race, other race, and being married were all independent risk factors for DHM non-consent.

Two qualitative studies conducted in Africa identified barriers to donor human milk use.^12,13 In South Africa, issues related to nonuse were related to safety and uneasiness using another mother's milk.¹² In Nigeria, identified barriers included transference of disease or genetic traits and religious/cultural beliefs.¹³ To our knowledge, this question has not been previously evaluated in the context of a developed country's neonatal ICU. Given the relatively high prevalence of DHM use in neonatal ICUs, these findings may provide insight into DHM consent.^10,11 Such insight may aid clinicians in developing appropriate guidelines regarding the DHM consent process.

This study has several limitations to acknowledge. First, this is a single-center study conducted in a Level IV inner-city neonatal ICU. Consequently, these findings are only generalizable to those satisfying the inclusion criteria for DHM use in this particular setting (i.e., mothers of infants born ≤32 weeks of gestation or ≤1,800 g). However, given that all qualifying families were approached for DHM consent, these findings represent population-level data within this particular setting. Second, although we identified two statistically significant independent predictors of DHM consent status, the point estimates may be interpreted as imprecise given the relatively wide confidence intervals. However, we statistically demonstrated the adequacy of this predictive model's fit. Third, specific reasons for DHM non-consent are descriptive in nature but were not systematically collected in the early part of the study period. It is not clear if the documented results for non-consent are representative of the entire study period. Fourth, it is unclear from these findings whether infant acuity is an independent predictor of DHM consent status. Further research should systematically evaluate timing of consent/non-consent and specific measures of infant acuity.

Our observed results have several strengths to emphasize, particularly related to study design and methodological approach. This study used prospectively collected clinical data and included numerous maternal and infant factors. However, these data points were not driven by published data. Given the paucity of previous research on this topic, we evaluated as many potential predictors as possible to generate an inclusive predictive model. We applied a conservative p value threshold for both inclusion into the multivariable model building process and for retention in the final model. We included a discussion of model fit adequacy and determined that our data sufficiently fit the model, further supporting the validity of these results. The transparency related to the model building process will allow other sites to replicate these results and evaluate the generalizability of these findings.

Conclusions

This study used a rigorous methodological approach to identify independent predictors of DHM consent status in a Level IV inner-city neonatal ICU. Black race, other race, and marital status statistically predicted DHM non-consent. These results are relevant to all neonatal ICUs who use DHM and to those who are developing DHM programs.

Footnotes

Acknowledgments

The authors are grateful for the outstanding assistance provided by Joseph Duckett for database development and by Meghan Dematta for data entry.

Disclosure Statement

No competing financial interests exist.

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