title: Breastfeeding duration related to practised contraception in the Netherlands.
abstract: OBJECTIVE
  The aim of this study was to gain insight into contraception practised and related to breastfeeding duration.
  
  
  METHODS
  Mothers with infants up to 6 months received a questionnaire on infant feeding (breast or formula feeding) and contraception (hormonal or non-hormonal methods). Estimates of the time interval between resuming contraception and cessation of lactation was calculated by Chained Equations Multiple Imputation.
  
  
  RESULTS
  Of all women (n = 2710), 30% choose condoms, 22% the combined oral contraceptive pill (OCP) and few other methods. Breastfeeding was started by 80%, and 18% continued up to 6 months. Of the breastfeeding mothers, 5% used hormonal contraception; 7% of women who used hormonal contraception practised breastfeeding. After adjustment for background variables, the use of OCP is strongly associated with formula feeding: after delivery to the third month postpartum, the crude OR being 17.5 (95% CI: 11.3-27.0), the adjusted OR 14.5 (9.3-22.5); between the third and sixth month postpartum, respectively, 13.1 (95% CI: 8.6-19.9) and 11.7 (7.6-17.9). Of all breastfeeding women, 20-27% resumed OCP at 25 weeks postpartum and 80% introduced formula feeding. The time lag between these events is 6 weeks. Hormonal contraception was resumed after formula introduction.
  
  
  CONCLUSIONS
  Mothers avoid hormonal contraception during lactation; they change to formula feeding 6 weeks before they resume the OCP. To effectively promote longer duration of breastfeeding, the BFHI needs to address contraception as practised.
authors.affiliation: Netherlands Organization for Applied Scientific Research TNO Quality of Life, Leiden, The Netherlands. ko.vanwouwe@tno.nl
authors.forename: Jacobus P
authors.initials: JP
authors.lastname: van Wouwe
authors.forename: Caren I
authors.initials: CI
authors.lastname: Lanting
authors.forename: Paula
authors.initials: P
authors.lastname: van Dommelen
authors.forename: Pieter E
authors.initials: PE
authors.lastname: Treffers
authors.forename: Stef
authors.initials: S
authors.lastname: van Buuren
mesh_terms: D000293:Adolescent; D000328:Adult; D001942:Breast Feeding / Q000706:statistics & numerical data*; D016001:Confidence Intervals; D003268:Contraception Behavior / Q000706:statistics & numerical data*; D003270:Contraceptive Agents / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007774:Lactation; D008425:Maternal Behavior; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D016017:Odds Ratio; D011795:Surveys and Questionnaires; D013997:Time Factors; D055815:Young Adult
chemical_list: D003270:Contraceptive Agents