Note: Not all women who develop breast
cancer have had an induced abortion nor do all women who
have an induced abortion develop breast cancer.
Induced abortion is the most preventable risk factor for
breast cancer. Women who experience abortion are at greater
risk for developing the deadly disease. The correlation
of human research (1-8) with data obtained
in rodent experimental models (9) lends
support to the biological explanation of the Abortion Breast
Cancer (ABC) link. In addition a large body of epidemiological
research has repeatedly established that induced abortion
does, in fact, lead to greater risk of breast cancer in
women. Although research also exists that seeks to undermine
or deny that there is a link, a close look at much of the
research in question shows evidence of unacceptable and
unscientific research methods, which in turn results in
Research that Supports the Link Between
Abortion and Breast Cancer
Research that Denies the Link Between
Abortion and Breast Cancer
For More Information
Research that Supports
the Link Between Induced Abortion and Breast Cancer
Research that Denies
the Link Between Induced Abortion and Breast Cancer
- The US National Cancer Institute denies there is a link
between abortion and breast cancer. However, it took this
position in 2003 after a “workshop” of invited
experts in which the evidence supporting the ABC link
was not allowed to be presented. A dissenting opinion
by epidemiologist, Dr. Joel Brind, who was present at
the February 2003 workshop, can be read at: http://www.bcpinstitute.org/nci_minority_rpt.htm
- In March 2004, the British Journal Lancet published
a paper by Valerie Beral and her colleagues at Oxford
which denied the link between abortion and breast cancer.
Experts have claimed that this meta-analysis was seriously
flawed. The most obvious flaw is that numerous studies
which show a definite link between abortion and breast
cancer were omitted, for unscientific reasons…such
as "principle investigator could not be traced",
etc. It is noteworthy that if all of the studies inappropriately
excluded are combined, they show an 80% increase in breast
cancer risk following induced abortion.
For more information please read the following articles:
Abortion and Breast Cancer: The Link That Won't Go Away - by Dr. Angela Lanfranchi
The Science, Studies and Sociology of the Abortion Breast Cancer Link - by Dr. Angela Lanfranchi
Induced Abortion as an Independent Risk Factor for Breast Cancer: A Critical Review of Recent Studies Based on Prospective Data - by Dr. Joel Brind
Cancer Link Revisited - by Dr. Angela Lanfranchi
The Abortion-Breast Cancer
Connection - by Dr. Joel Brind
The Corruption of Science
by Ideology - by Edward J. Furton
- A 2007 study by Michel's et al (15) reported that “Among this predominantly pre-menopausal population, neither induced nor spontaneous abortion was associated with the incidence of breast cancer.”
Critique: While this conclusion was based on 10 years of follow-up of the large Harvard Nurses Study II group, Dr. Joel Brind has exposed several serious methodological concerns which “cast doubt on the validity of the overall results.”(16). The “failure to exclude recent exposures (to abortion), coupled with failure to include many appropriate cases and to apply appropriate statistical adjustments, all combine to lower the observed association” (39), a situation Brind characterizes as a “strong and pervasive bias” (39). Brind argues that with the appropriate adjustments to these data, it would reveal an increase in breast cancer risk ranging from 20-50% (39).
Critique: Inappropriate comparisons were made, comparing women who had aborted their pregnancies to those who had never been pregnant. Childlessness raises breast cancer risk, and this invalid comparison would minimize a positive finding with abortive women. The authors also merged induced and spontaneous abortion, which are biologically distinct events. Spontaneous abortion, especially early in pregnancy, is associated with lower than normal levels of pregnancy hormones, due to either a fetal or ovarian abnormality.
- The 2008 “California Teachers Study” (17) published in the journal Contraception, acknowledges the biological explanation supporting a link between abortion and breast cancer. The authors conclude however, that “we found no statistically significant association between any measure of incomplete pregnancy and breast cancer risk...” (391).
- The 1997 Melbye et al. study (18) is often touted as
an authoritative study proving that there is no link between
abortion and breast cancer. According to researcher, Joel
Brind, this study contains "such substantial departures
from proper statistical analysis as (1)
the breast cancer (the outcome variable) registry's antedating
(emphasis in original) the abortion (exposure variable)
registry by up to 5.5 years, and (2) the misclassification of some 60 000 women as not having
had abortions, who actually had legal abortions on record"
(10). Even with these major methodological
flaws, and even though in the body of the Melbye study
text it mentions that "with each one-week increase
in the gestational age of the fetus, there was a 3 percent
increase in the risk of breast cancer" (18)
and that in pregnancies that were aborted after 18 weeks
gestation, there was a statistically significant 89% risk
elevation, this study is consistently put forward as proof
that there is no association between abortion and breast
Those who assert that induced abortion does not increase
breast cancer risk, often postulate recall (or reporting)
bias in the literature as being responsible for the
appearance of a positive link. According to the recall
bias hypothesis, when women are interviewed, those with
breast cancer are more likely to reveal they had an
abortion than those who have not had breast cancer.
The first paper which claimed evidence of recall bias
was a 1991 Swedish study.(19) This
study initially concluded that 50% of women without
breast cancer had under-reported their abortions, while
it was assumed that 27% of the women in the study were
"over-reporting" their abortions, because
they were not recorded in the abortion registry used
by the authors. The often referred to recall bias hypothesis
is based solely on the purported results of the Swedish
study. However, an analysis of the same data by a research
group led by Janet Daling revealed the percentage of
under-reporting to actually be a mere 16%, and not statistically
significant. Daling also doubts the concept of "over-reporting",
as she states, "we believe that it is reasonable
to assume that virtually no women who truly did not
have an abortion would claim to have one” (14)
In a published letter (20), the authors
of the Swedish study acknowledged the claim of "over-reporting"
to be unfounded, and with that all significant evidence
of recall bias evaporates. They concede that "we
are not surprised to find some Swedish women confidentially
reporting having had induced abortions during the period
1966-74 that are not recorded as legally induced abortions…Some
women therefore had induced abortions abroad or unrecorded
terminations of pregnancy"(20).
The recall bias hypothesis has been tested by retrospective
studies comparing case-interview responses to corresponding
clinical records in which competent obstetricians document
induced abortions and miscarriages. In one study (21)
researchers found the same risk of breast cancer when
they used medical records as when they used retrospective
interviews of the same patients proving, once again,
that recall bias did not exist.(22)
Back to the top of the
In the Winter 2005 issue of the Journal of American Physicians and Surgeons, Dr. Joel Brind published a review of ten prospective studies published between 1996 and 2005 (18). While all of the reviewed studies conclude that there is no link between induced abortion and breast cancer, Brind maintains that they embody many serious methodologic weaknesses and flaws, including “cohort effects, substantial misclassification errors due to missing information in databases, inadequate follow-up times, inadequately controlled effects of confounding variables, and frank violations of the scientific method (105)”. He concludes that the flaws are “sufficient to invalidate their findings”(109), and that “these recent studies therefore do not invalidate the large body of previously published studies that established induced abortion as a risk factor for breast cancer” (105). View complete review here: http://www.jpands.org/vol10no4/brind.pdf
For more information
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