NEW YORK (Reuters Health), Oct 16 - Induced abortion does not affect the risk of breast cancer, according to findings published in the October issue of the International Journal of Cancer.
"It is well established that pregnancies that end in a full-term birth ultimately confer a protective effect on breast cancer risk," Dr. Gillian K. Reeves, of the University of Oxford, UK, and colleagues write. "By contrast, the effect of incomplete pregnancies on the risk of breast cancer has been less clear."
The researchers examined the role of spontaneous and induced abortion on breast cancer risk among 267,361 women enrolled in the European Prospective Investigation into Cancer and Nutrition between 1992 and 2000. They data came from 20 centers across nine countries.
The women were followed for a mean of 6.6 years. A total of 4805 women were diagnosed with incident invasive breast cancer during follow-up.
"Overall, almost two-thirds (63%) of women reported never having had any type of abortion, while about one-third (33%) reported having had at least one type of abortion," Dr. Reeves and colleagues report. "About 20% of women reported ever having had a spontaneous abortion compared to about 16% who reported ever having had an induced abortion." Only 3.8% of women reported having had both types of abortion.
Compared to women who had never had a spontaneous abortion, the relative risk of breast cancer was not significantly increased among those who had a spontaneous abortion (RR = 1.07). Women who reported having at least two spontaneous abortions had a slightly increased risk of breast cancer (RR = 1.20). The relative risk among women who ever had an induced abortion compared to those who never had an induced abortion was 0.95.
"Overall, the findings provide further unbiased evidence of the lack of an adverse effect of induced abortion on breast cancer risk," the team concludes.
Last Updated: 2006-10-16 11:22:15 -0400 (Reuters Health)
Int J Cancer 2006;119:1741-1745.
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![Overview of the study design. (A) The fully automated deep learning framework was developed to estimate body composition (BC) (defined as subcutaneous adipose tissue [SAT] in liters; visceral adipose tissue [VAT] in liters; skeletal muscle [SM] in liters; SM fat fraction [SMFF] as a percentage; and intramuscular adipose tissue [IMAT] in deciliters) from MRI. The fully automated framework comprised one model (model 1) to quantify different BC measures (SAT, VAT, SM, SMFF, and IMAT) as three-dimensional (3D) measures from whole-body MRI scans. The second model (model 2) was trained to identify standardized anatomic landmarks along the craniocaudal body axis (z coordinate field), which allowed for subdividing the whole-body measures into different subregions typically examined on clinical routine MRI scans (chest, abdomen, and pelvis). (B) BC was quantified from whole-body MRI in over 66,000 individuals from two large population-based cohort studies, the UK Biobank (UKB) (36,317 individuals) and the German National Cohort (NAKO) (30,291 individuals). Bar graphs show age distribution by sex and cohort. BMI = body mass index. (C) After the performance assessment of the fully automated framework, the change in BC measures, distributions, and profiles across age decades were investigated. Age-, sex-, and height-adjusted body composition reference curves were calculated and made publicly available in a web-based z-score calculator (https://circ-ml.github.io).](https://img.auntminnieeurope.com/mindful/smg/workspaces/default/uploads/2026/05/body-comp.XgAjTfPj1W.jpg?auto=format%2Ccompress&dpr=2&fit=crop&h=167&q=70&w=250)