Introduction:
The aim of this study is to examine whether a 12-month perinatal health intervention which combines continuous long-term antenatal education and continuous counseling /lactation support with the psychosocial support of women, is associated with the initiation and duration of breastfeeding.

Material and Methods:
The study was conducted in Fainareti’s Day Center in Athens (Greece), a primary mental health care setting, during a five-year period (January 2014–January 2019). It consisted of a sample of 1080 women who participated in a 12-month intervention program. Data were analysed through multiple analyses of variance and logistic regression analysis.

Results:
The vast majority (96.3%) of participating mothers initiated breastfeeding either exclusively (70.7%) or some of the time (25.6%), and only 3% of them exclusively gave formula in the first 24 h after giving birth. In this study, at the end of the 1st month postpartum, the rate of any breastfeeding remained exactly the same (96.4%) as in the 1st day in maternity hospital, as opposed to a previous Pan-Hellenic research, where it appeared to have decreased. The multivariate analyses of variance (MANOVA) showed that mothers who received larger (quantitatively) midwifery-led support (antenatally and postpartum), had a longer any breastfeeding duration and longer duration of breastfeeding without giving any formula, compared to mothers who did not receive any support or received less support (p = 0.015 and p = 0.015, respectively). In addition, according to the logistic regression analysis, the chance for exclusive breastfeeding at the end of the 6th month postpartum appeared to increase when the woman had received greater (quantitatively) midwifery-led support in the perinatal period (p = 0.034). It is worth mentioning that, women who did not experience any symptoms of mental health disorders during pregnancy and up 12 months postpartum had a longer any breastfeeding duration compared to those who had high scores on psychometric tools and probably suffered from a mental health disorder, and those who received long-term counselling/psychotherapy (p = 0.029 and p = 0.013, respectively). Finally, this study showed significant correlations between specific perinatal factors and exclusive and any breastfeeding duration, and breastfeeding duration without giving any formula. For example, exclusive breastfeeding at the 1st day (p < 0.001) and at the 1st month postpartum (p < 0.001) seemed to increase the chance of exclusive breastfeeding at the end of the 6th month postpartum.

Conclusions:
It is evident that perinatal and postnatal (until the 1st year postpartum) midwifery-led education, counselling and support on breastfeeding is a key strategy for the promotion of breastfeeding. Further research is needed in order to investigate the effectiveness of breastfeeding interventions, especially in countries with low rates of exclusive breastfeeding.