Risk of breast cancer associated with short-term use of oral contraceptives

Cancer Causes Control. 2007 Mar;18(2):189-98. doi: 10.1007/s10552-006-0086-7. Epub 2007 Jan 10.


Objective: To estimate breast cancer risk associated with short-term (<6 months) oral contraceptive use, and explore variation in estimates by use characteristics and medical, menstrual, and reproductive history.

Methods: We analyzed data from the Women's Contraceptive and Reproductive Experiences Study. Case subjects were white women and black women, 35-64 years old, diagnosed with invasive breast cancer in July 1994-April 1998. Control subjects identified by random-digit dialing were matched to case subjects by age, race, and study site. Conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

Results: Overall, short-term oral contraceptive use was not associated with breast cancer risk (OR = 1.0; 95% CI = 0.8-1.1). However, significant interaction between short-term use and menopausal status led to an observed increased breast cancer risk in pre-menopausal women (OR = 1.3; 95% CI = 1.0-1.7) and a reduced risk in post-menopausal women (OR = 0.8; 95% CI = 0.6-1.0) associated with short-term use. The association was more pronounced in women with non-contraceptive reasons for use and underlying risk factors for breast cancer.

Conclusions: These associations may result from underlying characteristics of users or unmeasured factors influencing duration of use and breast cancer risk.

Publication types

  • Multicenter Study
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Breast Neoplasms / epidemiology*
  • Case-Control Studies
  • Contraceptives, Oral / adverse effects
  • Contraceptives, Oral / therapeutic use*
  • Female
  • Humans
  • Middle Aged
  • Odds Ratio
  • Risk
  • SEER Program*
  • Time Factors
  • United States / epidemiology


  • Contraceptives, Oral