title: Effects of prolonged and exclusive breastfeeding on child behavior and maternal adjustment: evidence from a large, randomized trial.
abstract: OBJECTIVE
  The objective of this study was to assess the long-term effects of breastfeeding on child behavior and maternal adjustment.
  
  
  METHODS
  We followed up children who were in the Promotion of Breastfeeding Intervention Trial, a cluster-randomized trial of a breastfeeding promotion intervention based on the World Health Organization/United Nations Children's Fund Baby-Friendly Hospital Initiative. A total of 17,046 healthy, breastfeeding mother-infant pairs were enrolled from 31 Belarussian maternity hospitals and affiliated polyclinics; 13,889 (81.5%) were followed up at 6.5 years. Mothers and teachers completed the Strengths and Difficulties Questionnaire and supplemental questions bearing on internalizing and externalizing behavioral problems. Mothers also responded to questions concerning their relationships to their partner and child and their breastfeeding of subsequently born children.
  
  
  RESULTS
  The experimental intervention led to a large increase in exclusive breastfeeding at 3 months (43.3% vs 6.4%) and a significantly higher prevalence of any breastfeeding at all ages up to and including 12 months. No significant treatment effects were observed on either the mother or the teacher Strengths and Difficulties Questionnaire ratings of total difficulties, emotional symptoms, conduct problems, hyperactivity, peer problems, or prosocial behavior or on the supplemental behavioral questions. We found no evidence of treatment effects on the parent's marriage or on the mother's satisfaction with her relationships with her partner or child, but the experimental intervention significantly increased the duration of any breastfeeding, and mothers in the experimental group were nearly twice as likely to breastfeed exclusively the next-born child for at least 3 months.
  
  
  CONCLUSIONS
  On the basis of the largest randomized trial ever conducted in the area of human lactation, we found no evidence of risks or benefits of prolonged and exclusive breastfeeding for child and maternal behavior. Breastfeeding promotion does, however, favorably affect breastfeeding of the subsequent child.
authors.affiliation: Department of Pediatrics, McGill University Faculty of Medicine, Montreal, Quebec, Canada. michael.kramer@mcgill.ca
authors.forename: Michael S
authors.initials: MS
authors.lastname: Kramer
authors.forename: Eric
authors.initials: E
authors.lastname: Fombonne
authors.forename: Sergei
authors.initials: S
authors.lastname: Igumnov
authors.forename: Irina
authors.initials: I
authors.lastname: Vanilovich
authors.forename: Lidia
authors.initials: L
authors.lastname: Matush
authors.forename: Elena
authors.initials: E
authors.lastname: Mironova
authors.forename: Natalia
authors.initials: N
authors.lastname: Bogdanovich
authors.forename: Richard E
authors.initials: RE
authors.lastname: Tremblay
authors.forename: Beverley
authors.initials: B
authors.lastname: Chalmers
authors.forename: Xun
authors.initials: X
authors.lastname: Zhang
authors.forename: Robert W
authors.initials: RW
authors.lastname: Platt
mesh_terms: D000223:Adaptation, Psychological; D000367:Age Factors; D001942:Breast Feeding / Q000523:psychology* / Q000706:statistics & numerical data*; D002652:Child Behavior / Q000523:psychology*; D002657:Child Development / Q000502:physiology; D002675:Child, Preschool; D016001:Confidence Intervals; D005260:Female; D005500:Follow-Up Studies; D006293:Health Promotion; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008429:Maternal Welfare; D009034:Mother-Child Relations; D016017:Odds Ratio; D011336:Probability; D012016:Reference Values; D002094:Republic of Belarus; D018570:Risk Assessment; D012737:Sex Factors; D013997:Time Factors