donor milk volume and characteristics of donors and their children
TRANSCRIPT
Early Human Development 90 (2014) 209–212
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Early Human Development
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Donor milk volume and characteristics of donors and their children
Gemma Sierra-Colomina a, Nadia Raquel García-Lara a,b,⁎, Diana Escuder-Vieco a,b, Clara Alonso-Díaz a,Eva María Andrés Esteban c, Carmen Rosa Pallás-Alonso a,b
a Department of Neonatology, 12 de Octubre Hospital, Madrid, Spainb SAMID (Spanish Collaborative Maternal and Children Research) Network, Spainc Clinical Research and Epidemiology Unit, IMAS12-CIBERESP, 12 de Octubre Hospital, Madrid, Spain
⁎ Corresponding author at: Servicio de Neonatología, HMaterno-Infantil, Avenida de Córdoba sin número, 28913908272, +34 678307549 (mobile); fax: +34 913908
E-mail address: [email protected] (N.R. García-L
http://dx.doi.org/10.1016/j.earlhumdev.2014.01.0160378-3782/© 2014 Elsevier Ireland Ltd. All rights reserved
a b s t r a c t
a r t i c l e i n f oArticle history:
Received 1 October 2013Received in revised form 18 January 2014Accepted 31 January 2014Keywords:Donor milkHuman milk bankVolume donation
Background: Little is known regarding the effect of the characteristics of donors and their children on the volumeof donor milk delivered to a human milk bank (HMB).Aims: Our study aimed to determine the relationship between different social and demographic variables ofdonors and their infants with the volume of human milk delivered.Methods:We included donors accepted at the Hospital Doce de Octubre HMB from January 1st, 2009 until April31st, 2013, andwhohadfinished their donation. Data of social and demographic characteristics of the donors andtheir children, and the total volume of DHM given were obtained from our HMB database. Included variableswere previous donors, donor age, number of children, place of residence, gestational age of the infant at birth,
child's age at the start of the donation, hospital admission, and death of the infant.A linear regression model was used to study the relationship between independent variables that were signifi-cant in bivariate analysis and the volume of donated milk.Results: A total of 415 donations from 391womenwere included. Themedian volume ofmilk deliveredwas 3.1 l(IQR—interquartile range—1.3–8.3 l). In the linear regression model, previous donors, smaller gestational age ofchildren, and the start of donation at earlier stages of lactation were associated with a larger quantity of HMBdonated (p ≤ 0.001).Conclusion: Previous donors, smaller gestational age of children, and the start of donation at earlier stages oflactation are associated with a larger quantity of milk donated to the HMB.© 2014 Elsevier Ireland Ltd. All rights reserved.
1. Introduction
Nowadays there is a great demand for donor breastmilk, particularlyfor preterm infants and other newborns suffering from diverse medicalproblems [1]. Previous studies have described the function of humanmilk banks (HMBs) and the use of donor human milk (DHM) [2,3].However, little is known regarding the characteristics of milk donors[4–9] and even lesser regarding how these characteristics can influencethe amount of milk donated [6]. Only one published article [6] has stud-ied the relationship between the characteristics of breast milk donorsand how these characteristics could affect the amount of human milkdelivered. As a secondary objective of the research, they studied thevariables of age, level of education, employment, household income,marital status, ethnicity and number of children. They only found an
ospital 12 de Octubre, Edificio041 Madrid, Spain. Tel.: +34272.ara).
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inverse relationship between age and donation amount (youngerwomen donated more milk). As far as we know, no published studieshave focused on the influence of the characteristics of donors' childrensuch as gestational age at birth, admission to hospital, death, age atthe starting time of donation and the donation amount.
This study aims to determine the relationship between differentsocial and demographic variables of human milk donors and their chil-dren with the volume of human milk delivered.
2. Methods
2.1. Operation of the Human Milk Bank of the University HospitalDoce de Octubre
The HMB of the University Hospital Doce de Octubre was opened inDecember 2007 [10]. This is the only HMB in theMadrid community, inthe Spanish central region, which has a population of 7 million inhabi-tants. Integrated in the Neonatology Service of the same hospital, theHMB supplies DHM to admitted newborns under medical prescription.The HMB has no home-collection system.
210 G. Sierra-Colomina et al. / Early Human Development 90 (2014) 209–212
In the selection process, candidates filled in a lifestyle questionnairethat included social and demographic data about themselves and theirchild. Serology of hepatitis B, C, VIH 1 and 2, HTLV I and II, and syphiliswas performed in the women. Exclusion criteria included womenwith positive serology for the above-mentioned infections, and thoseexposed to any risk factor of a sexual or blood transmissible disease inthe last 6 months. Strict vegetarians, smokers, habitual alcohol con-sumers or drinkers, or those drinking more than two caffeine drinksper day were excluded. Womenwhowere donors during breastfeedingof previous infants and those who wanted to donate their surplus milkafter the death of their infant were accepted. There was no limit onthe age of the infant for donation ofmilk or on the volumeofmilk. Ques-tionnaire data are routinely included in theHMBdatabase. The databaseautomatically calculates the volume of milk that a mother donates assoon as it is registered.
2.2. Participants and procedures
All donors accepted into the HMB at Doce de Octubre Hospital fromJanuary 1st, 2009 until April 31st, 2013, and who had already finishedtheir donation were included in the study. Women who donated milkat different periods of time with regard to breastfeeding of more thanone of their children (previous donors) were included. The amount ofmilk donated during each period of timewas classed as a different dona-tion. All donors were asked for their authorization for their data to beused in a research study. Confidentialitywas provided to all participantswhowere informed about the terms of consent. All procedures followedwere in accordance with the ethical standards of the Ethical Committeeof the University Hospital Doce de Octubre.
The donors' social demographic data, such as age, place of residence,being previous donors and number of children, were studied. The fol-lowing information regarding the infants were also included: gestation-al age, hospital admission, death of an infant, and age at the start ofdonation.
2.3. Statistics
To describe the volume of human milk delivered, the median, inter-quartile range (IQR), and quartiles were used because the data did notfollow a normal distribution. A bar chart was also included (Fig. 1).
Continuous variables apart from donor age were categorized andtreated statistically as qualitative variables. Gestational age at birthwas categorized into three groups: b32 weeks, 32–36 weeks, andN37 weeks. The age of infants atwhichdonationwas begunwas catego-rized into two groups: b4 months and ≥4 months.
Percentages were computed for categorical variables, and mediansand IQRs were calculated to describe the continuous variables.
Fig. 1. The bar chart shows the numb
To study the relationship between social and demographic variablesof donors and their infants with the volume of human milk delivered,the chi-squared and Spearman's rho test were used. A linear regressionmodel was used to study the relationship between independentvariables that were significant in bivariate analysis and the volumeof donated milk. The logarithm of the volume of DHM was used asa continuous variable in the model. Significance was acquired withp b 0.05.
3. Results
3.1. Participant characteristics and volume of DHM delivered
A total of 415 donations of 391 women were included in the study.The median age of the women was 33.6 years (IQR: 31–36 years). Atotal of 93.2% (382/410) of women lived in Madrid. Among the donors,55.9% (229/409) were primiparous, 37.9% (155/409) had one infant,and 6.1% (25/409) had two or more children. A total of 5.8% (24/415)of women had donated milk with previous infants. A total of 23.1%(96/415) of donors had preterm infants; 9.9% (41/415) was under32 weeks of gestational age and 13.2% (55/415) was between 32 and36 weeks of gestational age. A total of 36.6% (152/415) of donors hadtheir infants admitted to the neonatal unit and 4.1% (17/415) died. Atotal of 65.1% (262/415) of women started delivering DHM when theirinfant was less than 4 months. The donors started donating whentheir children were at a median age of 2.9 months (IQR: 1.3–5.7), rang-ing from 0 to 28 months.
DHM volume is shown in Fig. 1. The median volume of milk deliv-ered was 3.1 l (IQR: 1.3–8.3 l), and it ranged from 0.04 l to 174 l. Thefirst quartile ranges from 0.04 to 1.26 l; the second quartile from 1.26to 3.1 l; the third quartile between 3.1 and 8.26 l and the fourth quartilefrom 8.26 to 174.92 l.
Regarding the bivariate analysis, there was no statistically significantrelationship between the donor age and the volume of milk delivered(p = 0.96). Mean and SD values (in brackets) of donor age (years) forevery quartile group were 33.1 [3,8] for the first quartile, 33.4 [4,6] forthe second quartile, 33.3 [4,6] for the third quartile and 33.3 [4,2] forthe fourth quartile. The results concerning the rest of the characteristics(that are categorical) and the amount of milk delivered (divided into 4quartiles groups) are shown in Table 1.
In the regression model, women who had been milk donors previ-ously donated significantly more milk than those who hadn't been do-nors previously. Similarly, the lower the gestational age of the infantand the sooner that donors started their donation, the more milk theydonated (Table 2). The place of residence and admission of the childto hospital did not modify the amount of donated milk.
er of donors that donated milk.
Table 1Relationship among the donors and their children characteristics and the amount of milk donated (quartiles). Bivariate analysis (N = 415 donations; 391 donors).
Volume of milk delivered p value
1st Quartile 2nd Quartile 3rd Quartile 4th Quartile
No. of donations*One (%) 26.1 26.1 25 22.7 0.001Two (%) 8.3 12.5 20.8 58.3
Residence*Outside Madrid (%) 7.1 21.4 53.6 17.9 0.002Madrid (%) 26.7 25.4 22.5 25.3
Number of children0 (%) 26.6 28.8 23.1 21.4 0.11 (%) 24 21.2 27.1 27.72 (%) 15.8 5.3 31.6 47.4≥3 (%) 25 41.6 16.6 16.6
Deceased infantNo (%) 25.1 25.6 23.9 25.4 0.159Yes (%) 23.5 17.6 47 11.7
Gestational age*b32 weeks (%) 7.3 14.6 19.5 58.5 0.000132–26 weeks (%) 27.3 20 18.2 34.5N37 weeks (%) 27 27.6 26.6 18.8
Child hospitalization*No (%) 30.4 27 22.8 19.7 0.001Yes (%) 15.8 22.4 28.3 33.5
Child age*b4 months (%) 18.3 23.6 27.9 30.1 0.0001≥4 months (%) 36.6 28.8 18.9 15.7
For every characteristic, percentages of donors that accomplish it for every quartile group of milk delivered are included. Chi-squared and rho Spearman tests were used. Significance wasacquired if p value was smaller than 0.05 (*).
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4. Discussion
This prospective, cross-sectional study showed that women whohad previous experience as a donor donated more milk. Additionally,the sooner they began donating and the lower the gestational age oftheir child was, the more milk they donated. By contrast, maternalage, the number of previous children, the place of residence, admissionto hospital and death of their child did not affect the volume of milkdelivered.
To the best of our knowledge, this is the first study to investigate therelationship between social and demographic characteristics of donorsand their infants with the amount of DHMdelivered. Only one previousstudy, with a much smaller sample (87 women), explored the relation-ship between the amount of milk donated and some of the characteris-tics of the donors [6]. This relationship was studied as a secondaryobjective. Furthermore, our study examined, for the first time, the rela-tionship between the amount of DHM delivered and the characteristicsof the donors' children.
Table 2Relationship among the volumes of donor humanmilk (Napierian logarithm) and donorsand their children variables (regression linear model).
Mean 95% CI p value
Constant 7.63 (6.69, 8.57)No previous donor Reference Reference ReferencePrevious donor* 1.56 (1.01, 2.11) p b 0.001Residence outside Madrid community Reference Reference ReferenceResidence in Madrid community −0.36 (−0.85, 0.14) p = 0.157Gestational age b 32 weeks Reference Reference ReferenceGestational age 32–36 weeks* −0.67 (−1.21, −1.30) p = 0.015Gestational age ≥ 37 weeks* −0.84 (−1.33, −0.34) p = 0.001Breastfeeding time (b4 months) Reference Reference ReferenceBreastfeeding time (≥4 months)* −0.63 (−0.91, −0.34) p b 0.001No child admission at hospital Reference Reference ReferenceChild admission at hospital 0.07 (−0.267, 0.41) p = 0.676
CI: confidence interval. Covariates for adjustment: previous donor, residence (Madridcommunity or outside), gestational age (b32, 32–36 and ≥37 weeks), breastfeedingtime (b4 months and ≥4 months) and admission or child. * was added to the variable ifp value was smaller than 0.05.
In the study referred to below [6], donor agewas inversely related tomilk donation amount. This relationship was not found in our study.
Our infant profile is similar to other reported milk banks [11,12].Most of thewomen delivered at term, but some had preterm infants. In-terestingly, womenwhohad themost preterm childrenmade larger do-nations than those who had late preterm or term infants. Consideringthat the earlier the gestational age, the longer the hospitalization, itwould be interesting to study the influence of the length of time donors'children admission on the milk delivered.
Previous donors donated more milk. A study of our group showedthat donors had a great sense of satisfaction with the donation experi-ence in our HMB [10]. This could be the main reason why a largervolume of milk was delivered than their first experience.
The death of their child was not significantly related to the milk de-livered to the HMB. Only 7 donors fulfilled this condition and the rangeof volume deliveredwas very large (0.96–13.29 l). For these donors, thegathered human milk volume varied enormously and depended on thelife span of their children and their own milk output.
The median DHM volume in our study was 3.1 l per woman (IQR:1.3–8.3 l). This volume was smaller compared with the median DHMin two previous studies (median: 18.10 l and 18.4 l per woman respec-tively) [6,11]. The absence of a home-collection system in our HMBcould have played a role in the difference reported. In a previousstudy regarding the problems and barriers of donors [10], the main ob-stacle reported by our donors was the absence of a transport system ofDHM.
With regard to the starting ofmilk donation, Norwegianwomen [13]start donating milk at a median of approximately 7 weeks after havinggiven birth (range: 1–21 weeks) and continue for a mean of 4 months(range: b1–13 months). In our study, most donors (63.2%) begantheir donation of milk when their newborn was less than 4 monthsold, and the median time after having given birth was 3.1 months. Weobserved that the sooner women started donating milk, the more milkthey donated. This finding could be partly explained by the larger milkoutput in the first six months of lactation [14].
The main limitation of our study is that our HMB does not have ahome-collection system. This could limit extrapolation of our resultsto other HMBs that have this service. Moreover, it would be interesting
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to study other factors, such as the length of time donors' children areadmitted and the effect of the social and family environment on thevolume of DHM donated [15–18].
In conclusion, this study identified some factors that can affect theamount of human milk donated. Women who are previous donors de-liver a greater volume of milk. Likewise, an earlier gestational age ofchildren at birth and the start of donation at earlier stages of lactationare associated with a larger quantity of donated DHM. A better under-standing of the factors that affect the volume of DHM could boost thedonation process and improve the satisfaction of the donors.
Conflicts of interest statement
The authors have no conflicts of interest to declare.
Role of the funding source
This study was funded by the SAMID (Spanish Collaborative Mater-nal and Children and Development) Research Network. The fundingsource did not have any participation in the study design, in the collec-tion, analysis and interpretation data, in thewriting of the report, and inthe decision to submit the paper for publication.
Acknowledgments
The authors would like to thank Abraham Luis Pavón for his assis-tance and all the breast milk donors for their participation in this study.
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