It is often claimed that abortion leads to a higher risk of cancer. All reputable sources seem to be saying that this is nonsense and that there are no known health risks to abortion when compared to natural birth, but it is difficult to find links to the specific studies regarding this matter.
From the papers I have been able to find, there appears to be mixed evidence that there may be a link, but it is a weak effect.
- 2013-08-09 Induced abortion and breast cancer Wiley PubMed (Patrick Carroll): no abstract; article behind paywall
- 2013-07-19 Abortion-breast cancer study not valid for assessing overall association. criticizes a study by Braüner et al. which found no link. Can't seem to find the study to which it refers.
- 2004-03-27 [http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2804%2915835-
- 2004-06-05 Abortion and breast cancer: letter from David C. Reardon praising the above study
- 2002-05 [http://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(02)00723-
- 2001-04-28 Cancer paper retracted "the Journal of Clinical Oncology retracted a paper on high-dose chemotherapy for breast cancer on April 26 [-
- 1994-11-02 Risk of breast cancer among young women: relationship to induced abortion. (Daling JR, Malone KE, Voigt LF, White E, Weiss NS.) "Our data support the hypothesis that an induced abortion can adversely influence a woman's subsequent risk of breast cancer. However, the results across all epidemiologic studies of this premise are inconsistent--both overall and within specific subgroups. The risk of breast cancer should be reexamined in future studies of women who have had legal abortion available to them throughout the majority of their reproductive years, with particular attention to the potential influence of induced abortion early in life."