title: Stopping and switching contraceptive methods: findings from Contessa, a prospective longitudinal study of women of reproductive age in England.
abstract: BACKGROUND
  Discontinuation of, and change in, use of contraceptive methods contributes to high unplanned pregnancy rates. The aims of the Contessa study were to estimate the prevalence of and reasons for discontinuation and change and to assess the implications for preventive intervention.
  
  
  METHODS
  Prospective cohort study of 1091 potentially fertile women aged 18-49, carried out during 2008, using a sample drawn from the Health Survey for England 2006, a random probability survey of health. We carried out a baseline survey followed by three further waves, exploring patterns of contraceptive use, characteristics of women experiencing each, and reasons for discontinuation and change.
  
  
  RESULTS
  A percentage of 3.7 of women were at risk of unplanned pregnancy and discontinued and/or changed a contraceptive method in a year, compared with 4.7% who were at risk of unplanned pregnancy and used no method. Compared with continuous users, stoppers and switchers were younger, better educated and more likely to be single. Women discontinued or changed their contraceptive method for reasons of ease of use, reliability, side effects or concerns over health effects. Barely a quarter of such decisions were influenced by medical staff.
  
  
  CONCLUSIONS
  Effective strategies to aid contraceptive adherence have proved elusive but, if found, could reduce unplanned pregnancy rates appreciably. Understanding of the factors contributing to successful contraceptive practice is essential to prevention of unintended pregnancy.
authors.affiliation: Centre for Sexual and Reproductive Health Research, London School of Hygiene & Tropical Medicine, 15-17 Tavistock Place, London WC1H 9SH.
authors.forename: Kaye
authors.initials: K
authors.lastname: Wellings
authors.affiliation: Research Department of Infection & Population Health, University College, Mortimer Market, London, Mortimer Market Centre, London WC1E 6JB.
authors.forename: Nataliya
authors.initials: N
authors.lastname: Brima
authors.affiliation: NatCen Social Research, 35 Northampton Square, London, EC1V 0AX.
authors.forename: Katharine
authors.initials: K
authors.lastname: Sadler
authors.affiliation: Research Department of Infection & Population Health, University College, Mortimer Market, London, Mortimer Market Centre, London WC1E 6JB.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Copas
authors.affiliation: MRC Social and Public Health Sciences Unit, 4 Lilybank Gardens, Glasgow, G12 8RZ.
authors.forename: Lisa
authors.initials: L
authors.lastname: McDaid
authors.affiliation: Research Department of Infection & Population Health, University College, Mortimer Market, London, Mortimer Market Centre, London WC1E 6JB.
authors.forename: Catherine H
authors.initials: CH
authors.lastname: Mercer
authors.affiliation: NatCen Social Research, 35 Northampton Square, London, EC1V 0AX.
authors.forename: Sally
authors.initials: S
authors.lastname: McManus
authors.affiliation: Research Department of Infection & Population Health, University College, Mortimer Market, London, Mortimer Market Centre, London WC1E 6JB.
authors.forename: Judith
authors.initials: J
authors.lastname: Stephenson
authors.affiliation: Centre for Sexual and Reproductive Health Research, London School of Hygiene & Tropical Medicine, 15-17 Tavistock Place, London WC1H 9SH; School of Clinical Science and Community Health, University of Edinburgh, Little France Crescent, Edinburgh, EH16 4SB.
authors.forename: Anna
authors.initials: A
authors.lastname: Glasier
mesh_terms: D000293:Adolescent; D000328:Adult; D002755:Choice Behavior; D015331:Cohort Studies; D003268:Contraception Behavior; D003430:Cross-Sectional Studies; D004739:England / Q000453:epidemiology; D005193:Family Planning Services; D005260:Female; D019538:Health Care Surveys; D006801:Humans; D008137:Longitudinal Studies; D008875:Middle Aged; D011247:Pregnancy; D018873:Pregnancy Rate; D049168:Pregnancy, Unplanned; D015995:Prevalence; D011446:Prospective Studies; D012306:Risk; D055815:Young Adult
keywords: Contraceptive discontinuation; Contraceptive methods; Stopping; Switching; Unplanned pregnancy