Assessment of profiles of mothers interviewed before the opening of the milk bank and mothers who became HM donors

Table 1 describes the demographic and clinical characteristics of the women and their newborns in PRE, P1 and P2. From 391 lactating women interviewed in the PRE period, 55 (14%) showed intention to donate at all postpartum stages evaluated. These women were considered as potential candidates to be HM donors. Their mean age was similar to the donors of both post-opening periods, as well as the GA. The percentage of first-time mothers ranged from 54% (PRE) to 66% (P2). The majority of women in all periods were of Spanish nationality (PRE: n = 55, P1: n = 49, P2: n = 25) and from the province of Córdoba (PRE: n = 54, P1: n = 48, P2: n = 25). Regarding the educational level, a high proportion of women with higher education was especially observed in PRE and in P2 periods.

Table 1 Profile and characteristics of lactating women with intention to donate (PRE), donors (P1, P2) and their infants

Regarding the infant characteristics, most of them had a birth weight exceeding 2500 g and were born at full term.

Comparison of the donor profiles in the two post-opening periods

Significant differences were not observed in donor age, GA, or parity between the post-opening periods (Table 1). However, differences were detected in the educational level, with a homogeneous distribution in P1 period, while in P2 a higher proportion of donors had higher education (n = 17, 70.8%, p = 0.045). Regarding the occupation and the working situation at the starting time of donation, no significant differences were observed between the post-opening periods. Eighteen (40.5%) in P1 and seven donors (43.8%) in P2 were on maternity leave. However, it should be noted that a considerable proportion of donors were actively working when they started the donation (P1: n = 12, 32.4%; P2: n = 4, 25%), and a large part of them, especially in P2, at full-time (P1: n = 8, 66.7%; P2: n = 4, 100%).

Infants exhibited similar median birth weights between periods (P1: 3220 g; P2: 3000 g), with no statistically significant differences observed in the counts of low birth weight (< 2500 g) or prematurity. In both periods, a small proportion of women delivered infants who required hospitalization (P1: n = 2, 3.9%; P2: n = 3, 12%) or were very preterm infants (P1: n = 4, 7.8%; P2: n = 1, 4%) (Table 1).

A total of 13 (20.3%) women in P1 and five (16.7%) women in P2 initially registered as potential donors for the milk bank, but ultimately did not initiate the donation process. The women’s average age was 31.9 years, and their infant’s average GA was 38.5 weeks. Out of these, ten were first-time mothers, while 11 had a higher educational level and engaged in trained work. Only one woman had given birth to a low-weight infant, and four had experienced preterm deliveries. The reasons for not proceeding with the donation were as follows: withdrawal (72.2%), insufficient milk production (11.1%), COVID-19 (5.6%), mastitis (5.6%), and change of residence (5.6%).

Distribution of DHM volume and donation times

Table 2 shows the volumes of DHM and donation times. The range of total volume for both periods was remarkably wide (P1: 125–52,900 L; P2: 333–56,535 L). There were no significant differences observed in the daily or annual volume between periods, nor in the total donation time, which was very similar. However, significant differences were identified in the time that women took to initiate HM donation after the day of delivery, with a longer duration in P1 (median: 19 vs. 9 weeks, p = 0.047). Donors in P1 took almost five months to initiate donation after giving birth, while in P2, it took around two months.

Table 2 Volume of DHM and donation times for each period

Figure 1 displays the volume of DHM per month for both post-opening periods. A higher amount of DHM was collected in P2 than in the first year of the milk bank, despite having a smaller number of donors. May and July showed a higher DHM reception in both periods, with July 2020 having the highest volume of DHM (40 L). However, in both periods, the volume significantly decreased in August and then increased again in September. In October of P1, the volume remains similar to September, while in P2, it drops by 50%, and in November, it drops by 100% compared to September. There is a turning point in October, where the graph reverses, and the monthly received volume is higher in P1.

Fig. 1

Volume of DHM per month throughout the two post-opening periods. Orange diamonds: P1 (April 2019 – March 2020); Blue circles: P2 (April 2020 – March 2021). X-axis represents every month starting from April (P1: 2019, P2: 2020) until March (P1: 2020, P2: 2021)

Relationship between donor characteristics and DHM volume

Table 3 shows the association between donor profiles, their infants, and the total volume of DHM in each post-opening period. Results for GA showed a relationship with the donation volume in P2, with an additional three L donated by donors whose GA was < 37 weeks vs. those with ≥ 37 weeks (4.73 L vs. 1.80 L, p = 0.002).

Regarding the infant weight, donors from P1 with low birth weight infants donated more liters of milk compared with those whose infants had appropriate weight, regardless of the donation time (p = 0.020). However, in P2, this factor was not related to the donated volume.

No significant associations were observed between the starting time of donation and the total donated volume in either of the periods (Table 3).

Table 3 Association between donor characteristics (and their infants) and the total DHM volume in each post-opening periodRelationship between donor and newborn characteristics and time elapsed after childbirth to initiate donation

Neither the women’s age nor the GA showed a relationship with the starting time of donation in either period. Furthermore, neither being a first-time mother nor educational level were decisive factors in starting to donate (data not shown). However, in P2, first-time mothers tended to initiate donation later than non-first-time mothers did (22.63 ± 19.50 vs. 7.14 ± 11.14 weeks, p = 0.051).

The employment status showed an association with the time that women took to initiate the donation, both in P1 and P2. Specifically, in P1, women on maternity leave took less time (13.82 ± 11.74 weeks) to start donating compared to women who were actively working (42.72 ± 34.22 weeks, p = 0.002). During P2, unemployed women and women on maternity leave took significantly fewer weeks (15 ± 16.73; p = 0.006; and 7.82 ± 9.05 weeks; p < 0.001, respectively) to initiate donation after giving birth than women who were working at that time (46.82 ± 16.85 weeks). Additionally, differences were found between women on maternity leave and women on leave of absence, who took an average of 30.5 ± 10 weeks to initiate donation (p = 0.049).

For the characteristics of the newborns, there were no significant associations with the starting time of donation (data not shown).

Relationship between donor and newborn characteristics and donation times

Neither the donor age nor the GA showed a relationship with the total donation time in any of the post-opening periods (data not shown). Regarding educational level, there is a trend towards longer donation time in women with higher education during P2 (No studies / basic studies: 2.04 ± 1.40 vs. higher education: 3.93 ± 2.32 weeks, p = 0.061). The employment status at the starting time of the donation did not influence the length of donation time either (data not shown). Furthermore, although birth weight did not have a significant relationship, there was a trend to donate for a longer time in women whose infants had low birth weight in period P1 (birth weight < 2500 g: 6.14 ± 4.20 vs. birth weight ≥ 2500 g: 3.47 ± 2.99 weeks, p = 0.058). Regarding the condition of newborn hospitalization, no association was detected with the duration of donation time (data not shown).

The starting time of donation also did not have a relationship with the total time women spent donating (data not shown).

Dissemination media of the milk bank

Figure 2 shows all the information sources that have disseminated information about the milk bank and the possibility of becoming donors. Significant differences were observed between the two post-opening periods (p = 0.048). Breastfeeding support groups played a significant role in promoting awareness of the milk bank during its inaugural year (n = 20, 42.6%). However, in P2, the dissemination of information regarding HM donation through these groups dropped to 12.5% (n = 3), which aligned with the COVID-19 restrictions. In turn, the proportion of women who discovered the milk bank through the internet was higher during P2 (n = 9, 37.5%) compared with P1 (n = 14, 29.8%).

Fig. 2

Sources of information for promoting the milk bank. Orange bars: P1 (April 2019 – March 2020, total n = 47); Blue bars: P2 (April 2020 – March 2021, total n = 24)

Reasons for ceasing donation

Reasons why women discontinued donation did not show significant differences between periods. One of the most common was lack of time (P1: n = 12, 32.4%; P2: n = 5, 31.3%). In P2, the end of breastfeeding was the most important factor (n = 6, 37.5%). It is worth noting that in total, only one mother (who belonged to P1) decided to stop donating due to difficulties in the procedure, although for half of them, in both periods, it was an effort to come to the hospital to donate.