Regarding the IHAB-accredited maternity wards included in our evaluation, it is important to note that they are unevenly distributed across the country, with a high concentration in the North. It was therefore important for this evaluation to take into account the existing inequalities across different regions.

We used data from the National Perinatal Surveys of 2010 (n=), 2016 (n=), and 2021 (n=), each of which included more than 10,000 births (13,075, 10,919, and 10,209, respectively). The ranking of maternity wards was based on the 49 IHAB-certified maternity wards in metropolitan France; those in the process of obtaining certification were classified as non-certified (20 in 2010, 40 in 2016, and 31 in 2021). The online database of the National Institute of Statistics and Economic Studies (INSEE) was used for data concerning departmental characteristics.

We relied on a series of 5 mixed-effects multinomial regression models, progressively adding adjustment covariates: 1) IHAB accreditation of the maternity ward (yes/no) and the year of the survey, 2) infant and maternal characteristics, 3) maternity ward characteristics, 4) departmental characteristics and the spatial random effect, and 5) interaction terms. In Model 4, the spatial random effect at the departmental level allowed us to account for variation in breastfeeding rates across departments and the correlation between breastfeeding rates in neighboring departments. By further adjusting the model for French department variables and the random effect, the positive effect of the BFHI initiative on breastfeeding rates became more pronounced. This can be explained by the significant interregional variations in breastfeeding in metropolitan France and by the fact that BFHI-accredited maternity wards are unevenly distributed across the country. It was therefore essential to adjust the spatial structure of the data to isolate the effect of the BFHI. Notably, the spatial random effect accounted for more variability in the model than the selected departmental variables (percentage of migrant population, percentage of population with higher education).

In IHAB-accredited maternity wards, crude rates of exclusive breastfeeding were higher than in non-accredited maternity wards, while crude rates of mixed breastfeeding were lower than in non-accredited maternity wards. The same was true for rates adjusted for the variables mentioned above, across all models. On the other hand, the crude rate of total breastfeeding was lower in certified maternity wards, whereas the adjusted rate—accounting for individual covariates (maternal age, educational level, country of birth, marital status, situation at the end of pregnancy, household income, parity, body mass index, mode of delivery, time between delivery and the interview, birth weight, gestational age, time between delivery and the interview, neonatal transfer) was higher. This difference indicates that, regarding characteristics associated with breastfeeding, mothers giving birth in IHAB-certified maternity wards differed from those giving birth in non-certified maternity wards.

In our study, low-birth-weight newborns were breastfed less frequently than average-weight newborns, in both BFHI-accredited and non-accredited maternity wards. This is consistent with previous studies conducted in France, Spain, and Brazil (1–3). We found that the increase in exclusive breastfeeding rates and the decrease in mixed-feeding rates associated with BFHI accreditation were more pronounced among low-birth-weight newborns, thereby helping to narrow the existing gap between this vulnerable group and normal-weight babies.

The BFHI had a positive impact on breastfeeding rates among mothers with a medium to high level of education (two years of post-secondary education and beyond). For mothers with no education (who have not attended school) or with a primary school education, who represent approximately 2% of the study sample, the exclusive breastfeeding rate was lower in certified maternity wards, although with a wide confidence interval. These mothers belong to a minority group with specific characteristics that should be analyzed in greater depth.
Similarly, a cross-sectional study conducted in Belgium (4) showed that BFHI improved rates of initiation of exclusive breastfeeding primarily among subgroups of mothers who were already more likely to breastfeed (particularly those with a higher education level).

France has one of the lowest breastfeeding rates in Europe, with significant spatial and socioeconomic disparities. The results of our study demonstrate the positive impact of BFHI-accredited maternity wards on exclusive breastfeeding rates. They also indicate a lower rate of mixed feeding compared to non-accredited hospitals. We have demonstrated for the first time that this positive impact was even greater among low-birth-weight newborns. Our work has shown that implementing BFHI can improve breastfeeding practices in maternity wards, with a particular focus on vulnerable groups, such as mothers of low-birth-weight newborns, who tend to have lower breastfeeding rates.