Research across the globe on the risk factors that cause breast cancer has noted lifestyle as the key explanation. WHO also recognises that increasing urbanisation and adoption of western lifestyle contribute to the increasing incidence of breast cancer. At the time, when majority of studies attribute the increasing incidence of the disease to physical inactivity, dietary factors and obesity, recent research has noted that induced abortion may also be a risk factor.

The department of public health, Manipal University, published a paper in the Indian Journal of Community Medicine in May this year suggesting that abortion may be one of the causes of breast cancer in women.

Similarly, another study conducted by Jiangsu Province Institute of Cancer Research in China suggested that relationship between breast cancer and abortion may depend on menopausal status of the woman and induced abortion played a significant role in the development of breast cancer. The study was published in the Asian Pacific Journal of Cancer Prevention in January 2012. These two studies, first of their kind to be published in Asia, complement larger literature of studies published in the USA and Europe.

Various studies have suggested as well as disputed a statistical correlation between abortion and breast cancer. The medical community has been divided on the subject for over a decade as no large-scale lifetime studies have been conducted to confirm or dispute the hypothesis.

With a sample of 188 participants at the Shirdi Sai Baba Cancer Hospital and Research Centre, Karnataka, the study conducted in India noted that the age of menarche, age at first child birth and history of induced abortion were significant risk factors for breast cancer. All confirmed cases of breast cancer irrespective of their degree, between the age group 25 to 69 were included in the study as cases. The study was case controlled wherein half of the participants were ‘cases’ and half were ‘controls’.

This study holds relevance as the first in India subscribing to the abortion-breast cancer hypothesis. The hypothesis was first forwarded by Dr Jose Russo, director of the Breast Cancer and Environmental Research Center at the Fox Chase Cancer Center in Philadelphia in the 1980s, who has published many studies since.

According to Joel Brind, professor of biology and endocrinology at Baruch College, City University of New York and director at the non-profit Breast Cancer Prevention Institute based in New Jersey, abortion of a pregnancy interrupts the natural growth process of the breast, leaving cells at a high risk to cancer. “When a pregnancy is terminated unnaturally, the cancer-vulnerable breast tissue never has a chance to develop into the safer, milk-producing tissue,” he noted.

Upholding the association between induced abortion and the disease, the state of New Hampshire in USA passed a bill in March 2012 making it mandatory for doctors to tell women seeking abortion that abortion causes breast cancer.

Pro-abortion researchers supporting reproductive rights in India contest such research. Looking at it from the perspective of rights, they claim that it has been a long and hard struggle to achieve basic reproductive rights for women through policy change. Studies like the one in question should not be used to influence policies.

“Unsafe abortions continue to be one of the leading causes of maternal deaths in India and thus policy in India needs to be focussed on removing barriers to legal and safe abortions,” said Mohan Rao, professor at the Centre of Social Medicine and Community Health, Jawaharlal Nehru University, New Delhi.

Kerry McBroom, director of reproductive rights unit at non-profit Human Rights Law Network, based in New Delhi, added that there are multivariate causes for cancer and to isolate one factor amongst multitude is not appropriate for effecting policy changes. “The priority for public health policy making needs to be to make good abortion services available in India,” she added.

As per the data of the health ministry, 6,20,472 abortions were recorded in 2011 alone. Unofficial estimates of incidence are higher as more abortions are performed by non-approved institutions.