Original ArticlesBreastfeeding and Its Relation to Maternal Sensitivity and Infant AttachmentTharner, Anne PhD*,†,‡; Luijk, Maartje P.C.M. PhD*,†,‡; Raat, Hein MD, PhD§; IJzendoorn, Marinus H. PhD‡; Bakermans-Kranenburg, Marian J. PhD‡; Moll, Henriette A. MD, PhD‖; Jaddoe, Vincent W.V. MD, PhD†,‖,¶; Hofman, Albert MD, PhD¶; Verhulst, Frank C. MD, PhD*; Tiemeier, Henning MD, PhD*,¶ Author Information From the *Department of Child and Adolescent Psychiatry/Psychology; †Generation R Study Group, Erasmus University Medical Center, Rotterdam, The Netherlands; ‡Centre for Child and Family Studies, Leiden University, Leiden, The Netherlands; §Departments of Public Health; ‖Pediatrics; ¶Epidemiology, Erasmus University Medical Center, Rotterdam, The Netherlands. Received September 2011; accepted March 2012. The first phase of the Generation R Study is made possible by financial support from the Erasmus Medical Center Rotterdam, the Erasmus University Rotterdam, the Netherlands Organization for Health Research and Development (Zon Mw). The present study was supported by an additional grant from the Netherlands Organization for Health Research and Development (“Geestkracht” program grant 10.000.1003), and by additional grants from the Netherlands Organization for Scientific Research (grant no. 400-04-182; grant no. 452-04-306 (VIDI; VICI) to MJBK; grant no 017.106.370 (NWO ZonMW VIDI) to HT, and NWO SPINOZA prize to MHvIJ). Disclosure: The authors declare no conflict of interest. Address for reprints: Henning Tiemeier, MD, PhD, Department of Child and Adolescent Psychiatry/Psychology, Erasmus University Medical Center, P.O. Box 2060, 3000 CB Rotterdam, The Netherlands; e-mail: [email protected]. All the authors have made substantive intellectual contributions to this study by contributing to the design, acquisition, analysis and interpretation of data, drafting the article or revising it critically for important intellectual content, or approving the final version to be published. Journal of Developmental & Behavioral Pediatrics 33(5):p 396-404, June 2012. | DOI: 10.1097/DBP.0b013e318257fac3 Buy Metrics Abstract Objective: To examine the association of breastfeeding with maternal sensitive responsiveness and infant-mother attachment security and disorganization. Methods: We included 675 participants of a prospective cohort study. Questionnaires about breastfeeding practices were administered at 2 and 6 months postpartum. At 14 months, maternal sensitive responsiveness was assessed in a 13-minute laboratory procedure using Ainsworth's sensitivity scales, and attachment quality was assessed with the Strange Situation Procedure. Mothers were genotyped for oxytocin receptor genes OXTR rs53576 and OXTR rs2254298. Linear regressions and analyses of covariance adjusted for various background variables were conducted. We tested for mediation and moderation by maternal sensitive responsiveness and maternal oxytocin receptor genotype. Results: Continuous analyses showed that longer duration of breastfeeding was associated with more maternal sensitive responsiveness (B = 0.11, 95% confidence interval [CI] 0.02; 0.20, p < .05), more attachment security (B = 0.24, 95% CI = 0.02; 0.46, p < .05), and less attachment disorganization (B = −0.20, 95% CI −0.36; −0.03, p < .05). Duration of breastfeeding was not related to the risk of insecure-avoidant or insecure-resistant versus secure attachment classification, but longer duration of breastfeeding predicted a lower risk of disorganized versus secure attachment classification (n = 151; odds ratio [OR] = 0.81, 95% CI 0.66 to 0.99, p = .04). Maternal sensitive responsiveness did not mediate the associations, and maternal oxytocin receptor genotype was not a significant moderator. Conclusions: Although duration of breastfeeding was not associated with differences in infant-mother attachment classifications, we found subtle positive associations between duration of breastfeeding and sensitive responsiveness, attachment security, and disorganization. © 2012 Lippincott Williams & Wilkins, Inc.