Epidemiologic studies have been inconsistent in suggesting an association between abortion and breast cancer risk. Whether the protection provided by a full-term pregnancy also results from a short-term pregnancy or whether a prematurely terminated pregnancy could increase the risk of breast cancer is unclear. Data from a large, international collaborative study were used to evaluate the association between abortions, whether spontaneous or induced, and breast cancer risk. The data from seven countries included 3,958 breast cancer cases and 11,538 hospital controls with information on abortion history obtained through interviews. Compared with nulliparous women with no abortion (baseline), the odds ratios (OR) and 95 percent confidence intervals (CI) were: for nulliparous women with a history of prior abortion, 0,86 (CI=0.68–1.08); for parous women with no history of abortion, 0.63 (CI=0.57–0.69); for parous women with abortion before first birth, 0.82 (CI=0.69–0.97); and, for parous women with abortion only after first birth, 0.70 (CI=0.63–0.79). When restricting analysis to parous women, those with a history of abortion exhibited an elevated OR suggesting a 29 percent risk increase if the incomplete pregnancy occurred before first birth (CI=1.16–1.36) and an 11 percent risk increase for abortion only after first birth (CI=1.02–1.20) compared with women without such history. The associations observed were stronger among the youngest women. These results do not support a large overall association between abortion and breast cancer risk.
This is a preview of subscription content, access via your institution.
Buy single article
Instant access to the full article PDF.
Tax calculation will be finalised during checkout.
Subscribe to journal
Immediate online access to all issues from 2019. Subscription will auto renew annually.
Tax calculation will be finalised during checkout.
Pike MC, Henderson BE, Casagrande JT, Rosario I, Gray GE. Oral contraceptive use and early abortion as risk factors for breast cancer in young women. Br J Cancer 1981; 43: 72–6.
Salber EJ, Trichopoulos D, MacMahon B. Lactation and reproductive histories of breast cancer patients in Boston, 1965–66. JNCI 1969; 43: 1013–24.
Lowe CR, MacMahon B. Breast cancer and reproductive history of women in South Wales. Lancet 1970; 1(639): 153–7.
Ravnihar B, MacMahon B, Lindtner J. Epidemiologic features of breast cancer in Slovenia, 1965–1967. Eur J Cancer 1971; 7: 295–306.
Mirra AP, Cole P, MacMahon B. Breast cancer in an area of high parity: São Paulo, Brazil. Cancer Rees 1971; 31: 77–83.
Stavraky K, Emmons S. Breast cancer in premenopausal and postmenopausal women. JNCI 1974; 53: 647–54.
Toti A, Piffanelli A, Pavanelli T, et al. Possible indication of breast cancer risk through discriminant functions. Cancer 1980; 46: 1280–5.
Kelsey JL, Fischer DB, Holford TR, et al. Exogenous estrogens and other factors in the epidemiology of breast cancer. JNCI 1981; 67: 327–33.
Brinton LA, Hoover R, Fraumeni JFJr. Reproductive factors in the aetiology of breast cancer. Br J Cancer 1983; 47: 757–62.
Le MG, Bachelot A, Doyon F, Kramar A, Hill C. Oral contraceptive use and breast or cervical cancer: preliminary results of a French case-control study. In: Wolff JP, Scott JS, eds. Hormones and Sexual Factors in Human Cancer Aetiology. New York, NY (USA): Elsevier, 1984: 139–47.
Levshin VF, Chepurko AD. Reproductive anamnesis and mammary carcinoma (in Russian) Sov Med 1986; 6: 15–21.
Rosenberg L, Palmer J, Kaufman DW, Strom BL, Schottenfeld D, Shapiro S. Breast cancer in relation to the occurrence and time of induced and spontaneous abortion. Am J Epidemiol 1988; 127: 981–9.
Yuan JM, Yu MC, Ross RK, Gao YT, Henderson B. Risk factors for breast cancer in Chinese women in Shanghai. Cancer Res 1988; 48: 1949–53.
Adami HO, Bergstrom R, Lund E, Meirik O. Absence of association between reproductive variables and the risk of breast cancer in young women in Sweden and Norway. Br J Cancer 1990; 62: 122–6.
Parazzini F, La Vecchia C. Spontaneous and induced abortions and risk of breast cancer. Int J Cancer 1991; 48: 816–20.
Parazzini F, La Vecchia C, Negri E, Franceschi S, Bocciolone L. Menstrual and reproductive factors and breast cancer in women with family history of the disease. Int J Cancer 1992; 51: 677–81.
Segi M, Fukushima I, Fujisaki S et al. An epidemiological study on cancer in Japan. GANN 1957; 48(supp): 1–63.
Valaoras VG, MacMahon B, Trichopoulos D, Polychronopoulou A. Lactation and reproductive histories of breast cancer patients in greater Athens, 1965–67. Int J Cancer 1969; 4: 350–63.
Yuasa S, MacMahon B. Lactation and reproductive histories of breast cancer patients in Tokyo, Japan. Bull WHO 1970; 42: 195–204.
Lin TM, Chen KP, MacMahon B. Epidemiologic characteristics of cancer of the breast in Taiwan. Cancer 1971; 27: 1497–504.
Soini I. Risk factors of breast cancer in Finland. Int J Epidemiol 1977; 6: 365–73.
Choi NW, Howe R, Miller B, et al. An epidemiologic study of breast cancer. Am J Epidemiol 1978; 107: 510–21.
Dvoirin VV, Medvedev AB. The role of reproductive history in breast cancer causation (in Russian) In: Methods and Results of Studies of Breast Cancer Epidemiology. Tallinn 1978: 53–6.
Hirohata T, Shigematsu T, Nomura AMY, Nomura Y, Horie A, Hirohata I. Occurrence of breast cancer in relation to diet and reproductive history: a case-control study in Fukuoka, Japan. NCI Monographs 1985; 69: 187–90.
Ewert M, Duffy SW. Risk of breast cancer in relation to reproductive factors in Denmark. Br J Cancer 1988; 58: 99–104.
Howe HL, Senie RT, Bzduch H, Herzfeld P. Early abortion and breast cancer risk among women under age 40. Int J Epidemiol 1989; 18: 300–4.
Andrieu N, Clavel F, Gairard B, et al. Familial risk of breast cancer and abortion. Cancer Detect Prev 1994; 18: 51–5.
Paffenbarger RS, Kampert JB, Chang HG. Characteristics that predict risk of breast cancer before and after the menopause. Am J Epidemiol 1980; 112: 258–68.
Vessey MP, McPherson K, Yeates D, Doll R. Oral contraceptive use and abortion before first term pregnancy in relation to breast cancer risk. Br J Cancer 1982; 45: 327–31.
Gandra L, Barros H, Moreira A, Calheires F, Magalhaes N. Factores de risco para o canero da mama: um estudo caso-controlo. A Medica Portuguesa 1993; 6: 129–33.
Hajimichael OC, Boyle CA, Meigs JW. Abortion before first livebirth and risk of breast cancer. Br J Cancer 1986; 53: 281–4.
Kvåle G, Heuch I, Eide GE. A prospective study of reproductive factors and breast cancer. Am J Epidemiol 1987; 126: 831–41.
Lindefors Harris BM, Eklund G, Meirik O, Rutqvist LE, Wiklund K. Risk of cancer of the breast after legal abortion during first trimester: a Swedish register study. Br Med J 1989; 299: 1430–2.
Sellers TA, Potter JD, Severson RK, et al. Difficulty becoming pregnant and family history as interactive risk factors for postmenopausal breast cancer: the Iowa Women's Health Study. Cancer Causes Control 1993; 4: 21–8.
Janerich DT, Hoff MB. Evidence for a crossover in breast cancer risk factors. Am J Epidemiol 1982; 116: 737–42.
Lubin JH, Burns PE, Blot WJ, et al. Risk factors for breast cancer in women in northern Alberta, Canada, as related to age at diagnosis. JNCI 1982; 68: 211–7.
Pathak DR, Speizer FE, Willett WC, Rosner B, Lipnick RJ. Parity and breast cancer risk: possible effect on age at diagnosis. Int J Cancer 1986; 37: 21–5.
Bruzzi P, Negri E, La Vecchia C, et al. Short term increase in risk of breast cancer after full term pregnancy. Br Med J 1988; 297: 1096–8.
Williams EMI, Jones L, Vessey MP, McPherson K. Short term increase in risk of breast cancer associated with full pregnancy. Br Med J 1990; 300: 578–9.
Hsieh C-c, Pavia M, Lambe M, et al. Dual effect of parity on breast cancer risk. Eur J Cancer 1994; 30A: 969–73.
Lambe M, Hsieh C-c, Trichopoulos D, Ekbom A, Ravia M, Adami HO. Transient increase in the risk of breast cancer after giving birth. N Engl J Med 1994; 331: 5–9.
Russo J, Russo IH. Susceptibility of the mammary gland to carcinogenesis. II, Pregnancy interruption as a risk factor in tumor incidence. Am J Pathol 1980; 100: 497–511.
Russo J, Tay LK, Russo IH. Differentistion of the mammary gland and susceptibility to carcinogenesis. Breast Cancer Res Treat 1982; 2: 5–73.
MacMahon B, Lin TM, Lowe CR, et al. Lactation and cancer of the breast. Bull WHO 1970; 42: 185–94.
MacMahon B, Cole P, Lin TM, et al. Age at first birth and breast cancer risk. Bull WHO 1970; 43: 209–21.
Trichopoulos D, Hsieh C-c, MacMahon B, et al. Age at any birth and breast cancer risk. Int J Cancer 1983; 31: 701–4.
Hsieh C-c, Trichopoulos D, Katsouyanni K, Yuasa S. Age at menarche, age at menopause, height and obesity as risk factors for breast cancer: associations and interactions in an international case-control study. Int J Cancer 1990; 46: 796–800.
Hsieh C-c, Trichopoulos D. Breast size, handedness and breast cancer risk. Eur J Cancer 1991; 27: 131–5.
Hsieh C-c, Goldman M, Pavia M, et al. Breast cancer risk in mothers of multiple births. Int J Cancer 1993; 54: 81–4.
Easton DF, Peto J, Babiker AGAG. Floating absolute risk: an alternative to relative risk in survival and case-control analysis avoiding an arbitrary reference group. Stat Med 1991; 10: 1025–35.
MacMahon B. Reproduction and cancer of the breast. Cancer 1993; 71: 3183–8.
Russo J, Russo IH. Development of the human mammary gland. In: Neville MC, Daniel C, eds. The Mammary Gland. New York, NY (USA): Plenum Press, 1987: 67–93.
Russo J, Rivera R, Russo IH. Influence of age and parity on the development of the human breast. Breast Cancer Res Treat 1992; 23: 211–8.
Rosner B, Colditz GA, Willett WC. Reproductive risk factors in a prospective study of breast cancer: the Nurses' Health Study. Am J Epidemiol 1994; 139: 819–35.
Willett WC, Stampfer MJ, Colditz GA, Rosner BA, Hennekens CH, Speizer FE. Moderate alcohol consumption and the risk of breast cancer. NEJM 1987; 316: 1174–80.
Schatzkin A, Jones DY, Hoover RN, et al. Alcohol consumption and breast cancer in the epidemiologic follow-up study of the first National Health and Nutrition Examination Survey. NEJM 1987; 316: 1169–73.
Longnecker MP. Alcohol beverage consumption in relation to risk of breast cancer: meta-analysis and review. Cancer Causes Control 1994; 5: 73–82.
Ms Michels and Drs Hsieh, Trichopoulos, and Willett are with the Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA. Dr Willett is also affiliated with the Department of Nutrition, Harvard School of Public Health, and Channing Laboratory, Department of Medicine, brigham and Women's Hospital and Harvard Medical School, Boston, MA. Address correspondence to Ms Michels, Department of Epidemiology, Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA.
About this article
Cite this article
Michels, K.B., Hsieh, Cc., Trichopoulos, D. et al. Abortion and breast cancer risk in seven countries. Cancer Causes Control 6, 75–82 (1995). https://doi.org/10.1007/BF00051683
- breast cancer
- international comparison