Search tips
Search criteria 


Logo of brjcancerBJC HomepageBJC Advance online publicationBJC Current IssueSubmitting an article to BJCWeb feeds
Br J Cancer. 1999 May; 80(3-4): 609–613.
Published online 1999 May 1. doi:  10.1038/sj.bjc.6690399
PMCID: PMC2362328

Preterm delivery and risk of breast cancer


To explore the risk of breast cancer in relation to the length of a pregnancy we tested whether a preterm delivery carries a higher risk of breast cancer than does a full-term delivery. Based on information from the Civil Registration System, and the National Birth Registry in Denmark, we established a population-based cohort of 474 156 women born since April 1935, with vital status and detailed parity information, including the gestational age of liveborn children and stillbirths. Information on spontaneous and induced abortions was obtained from the National Hospital Discharge Registry and the National Registry of Induced Abortions. Incident cases of breast cancer in the cohort (n = 1363) were identified through linkage with the Danish Cancer Registry. The period at risk started in 1978 and continued until a breast cancer diagnosis, death, emigration, or 31 December, 1992, whichever occurred first. After adjusting for attained age, parity, age at first birth and calendar period, we observed the following relative risks of breast cancer for different lengths of the pregnancy: < 29 gestational weeks = 2.11 (95% confidence interval 1.00–4.45); 29–31 weeks = 2.08 (1.20–3.60); 32–33 weeks = 1.12 (0.62–2.04); 34–35 weeks = 1.08 (0.71–1.66); 36–37 weeks = 1.04 (0.83–1.32); 38–39 weeks = 1.02 (0.89–1.17); 40 weeks = 1 (reference). Parous women who had a preterm delivery below 32 weeks gestation had a 1.72-fold (1.14–2.59) increased risk of breast cancer compared with other parous women. In conclusion, a preterm delivery of 32+ weeks gestation did not significantly increase a woman's risk of contracting breast cancer. Only for the very small group of women with preterm deliveries of less than 32 weeks gestation did we observe an increased risk. © 1999 Cancer Research Campaign

Keywords: breast cancer, reproductive factors, gestational age, preterm, cohort study, population-based

Full Text

The Full Text of this article is available as a PDF (76K).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Adami HO, Bergström 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 Jul;62(1):122–126. [PMC free article] [PubMed]
  • Brinton LA, Hoover R, Fraumeni JF., Jr Reproductive factors in the aetiology of breast cancer. Br J Cancer. 1983 Jun;47(6):757–762. [PMC free article] [PubMed]
  • Calle EE, Mervis CA, Wingo PA, Thun MJ, Rodriguez C, Heath CW., Jr Spontaneous abortion and risk of fatal breast cancer in a prospective cohort of United States women. Cancer Causes Control. 1995 Sep;6(5):460–468. [PubMed]
  • Choi NW, Howe GR, Miller AB, Matthews V, Morgan RW, Munan L, Burch JD, Feather J, Jain M, Kelly A. An epidemiologic study of breast cancer. Am J Epidemiol. 1978 Jun;107(6):510–521. [PubMed]
  • Daling JR, Malone KE, Voigt LF, White E, Weiss NS. Risk of breast cancer among young women: relationship to induced abortion. J Natl Cancer Inst. 1994 Nov 2;86(21):1584–1592. [PubMed]
  • Hunter DJ, Willett WC. Diet, body size, and breast cancer. Epidemiol Rev. 1993;15(1):110–132. [PubMed]
  • Kvåle G, Heuch I, Eide GE. A prospective study of reproductive factors and breast cancer. I. Parity. Am J Epidemiol. 1987 Nov;126(5):831–841. [PubMed]
  • Melbye M, Wohlfahrt J, Olsen JH, Frisch M, Westergaard T, Helweg-Larsen K, Andersen PK. Induced abortion and the risk of breast cancer. N Engl J Med. 1997 Jan 9;336(2):81–85. [PubMed]
  • Michels KB, Hsieh CC, Trichopoulos D, Willett WC. Abortion and breast cancer risk in seven countries. Cancer Causes Control. 1995 Jan;6(1):75–82. [PubMed]
  • Naeye RL. Maternal body weight and pregnancy outcome. Am J Clin Nutr. 1990 Aug;52(2):273–279. [PubMed]
  • Newcomb PA, Storer BE, Longnecker MP, Mittendorf R, Greenberg ER, Willett WC. Pregnancy termination in relation to risk of breast cancer. JAMA. 1996 Jan 24;275(4):283–287. [PubMed]
  • Palmer JR, Rosenberg L. Cigarette smoking and the risk of breast cancer. Epidemiol Rev. 1993;15(1):145–156. [PubMed]
  • Pickering RM, Deeks JJ. Risks of delivery during the 20th to the 36th week of gestation. Int J Epidemiol. 1991 Jun;20(2):456–466. [PubMed]
  • Polednak AP, Janerich DT. Characteristics of first pregnancy in relation to early breast cancer. A case-control study. J Reprod Med. 1983 May;28(5):314–318. [PubMed]
  • Rao DN, Ganesh B, Desai PB. Role of reproductive factors in breast cancer in a low-risk area: a case-control study. Br J Cancer. 1994 Jul;70(1):129–132. [PMC free article] [PubMed]
  • Rosenberg L. Induced abortion and breast cancer: more scientific data are needed. J Natl Cancer Inst. 1994 Nov 2;86(21):1569–1570. [PubMed]
  • 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 Aug;100(2):497–512. [PubMed]
  • Storm HH. The Danish Cancer Registry, a self-reporting national cancer registration system with elements of active data collection. IARC Sci Publ. 1991;(95):220–236. [PubMed]
  • Williams MA, Mittendorf R, Stubblefield PG, Lieberman E, Schoenbaum SC, Monson RR. Cigarettes, coffee, and preterm premature rupture of the membranes. Am J Epidemiol. 1992 Apr 15;135(8):895–903. [PubMed]
  • Zhang J. Differences between spontaneous and induced abortions as risk factors for breast cancer. Epidemiology. 1996 May;7(3):316–318. [PubMed]

Articles from British Journal of Cancer are provided here courtesy of Cancer Research UK