Effectiveness of a group educational intervention – prolact - in primary care to promote exclusive breastfeeding: a cluster randomized clinical trial
Authors: Santamaría- Martín María Jesús , Martín-Iglesias Susana , Schwarz Christine , Rico-Blázquez Milagros , Portocarrero-Nuñez Julián Alexander , Diez-Izquierdo Laura , Llamosas-Falcón Laura , Rodríguez-Barrientos Ricardo , Del-Cura-González Isabel ,   Grupo PROLACT, Martín-Llorente Francisca , Casero-Perona Leopoldo , Plasencia-Plasencia Paz , Sánchez-Méndez Marta Yolanda , Santamaría-Medrano Pilar , Mielgo-Salvador Rebeca , Cañón-Cañón Carolina , Valor-Sánchez Dolores , Fernández-Fernández Ramona , López-Lozano Soledad , Morales-Montalva Marisol , Pérez-Mañanes María Elena , Durand-Rincón Isabel , Valdecantos-Coscollano Sara , Hernández-Hernández Verónica , Noceco-Paredes Maria Dolores , Malde-García Clara , Miranda-Martín Ma Ángeles , de la Peña Antón Nuria , Martín-Díaz Elena , Robas-García Dolores , Parra-Moro Manuel , Ruiz-del-Castillo María Concepción , Geijo-Rincón Maria Jesús , Rivero-Garrido Carmen , Alameda-Hernández María Gema , González-Macías Miriam , Coghen-Vigueras Isabel , Arenas-Yaguez Raquel , San Pablo-Campos Carolina , Prados-Bueno Rosa M , Bejarano-López Ma Adoración , García-Ruiz Natividad , Magdaleno-Del-Rey Gema , Tirado-Jiménez Lucía , Santamaria-Martín Ma Jesús , Reviriego-Gutierrez Asunción , Soto-Almendro Beatriz , García-Romero Paula , Zarco-Cid Elena , Villa-Arranz María , Fernández-de-Velasco Alma Mejía , Anta-Rodríguez Laura , Sánchez-Prieto-Emmanuel María Isabel , Barrios-García Luz Divina , Lozano-Adeva Carmen , Casado-García Luis Mariano , Gómez-Pérez Lourdes , Martínez-Sierra Ma Dolores , Escobar-García Martha Olga , Guerra-Nieto Ma Dolores , Azcona-Domínguez Elena , Delgado-Domínguez María Ángeles , Verdugo-Hernández Rafael 
Published: February 2022

Abstract
Background
The rates of exclusive breastfeeding at 6 months in Spain are far from recommended by the World Health Organization, which is 50% by 2025. Evidence of the effectiveness of group interventions in late postpartum is limited. The objective of this study was to evaluate the effectiveness of the PROLACT group educational intervention for increasing the proportion of mother-child dyads with exclusive breastfeeding at 6 months compared to the usual practice in primary care.

Method
Multicentre cluster randomized clinical trial. A total of 434 mother-child dyads who breastfed exclusively in the first 4 weeks of the children’s life and agreed to participate were included. The main outcome was exclusive breastfeeding at 6 months. Secondary variables were type of breastfeeding, reasons for abandonment, degree of adherence and satisfaction with the intervention. To study the effectiveness, the difference in the proportions of dyads with exclusive breastfeeding at 6 months was calculated, and the relative risk (RR) and number needed to treat (NNT) were calculated with their 95% CIs. To study the factors associated with the maintenance of exclusive breastfeeding at 6 months, a multilevel logistic regression model was fitted. All analyses were performed to intention to treat.

Results
The percentage of dyads with exclusive breastfeeding at 6 months was 22.4% in the intervention group and 8.8% in the control group. PROLACT intervention obtained an RR =2.53 (95% CI: 1.54–4.15) and an NNT = 7 (95%CI: 5–14). The factors associated with exclusive breastfeeding at 6 months were the PROLACT intervention, OR = 3.51 (95%CI: 1.55–7.93); age > 39 years, OR = 2.79 (95%CI: 1.02–7.6); previous breastfeeding experience, OR = 2.61 (95%CI: 1.29–5.29); income between 500 and 833.33 €, OR = 3.52 (95%CI 1.47–8.47).); planning to start work before the infant was 6 months old, OR = 0.35 (0.19–0.63) .

Conclusions
The PROLACT intervention in primary care is more effective than the usual practice for maintaining exclusive breastfeeding at 6 months, and can therefore be considered evidence-based practice for implementation in standard practice.

Trial registration
The trial was registered with ClinicalTrials.gov under code number NCT01869920 (03/06/2013).