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Women Who Delay First Pregnancy Into 30's Are At Increased Risk

British Journal of Cancer (2002) 86, 723-727; DOI: 10.1038   Cancer Research UK  F. Clavel-Chapelon et al


Having a miscarriage does not increase a woman's risk of breast cancer at any age, according to one of the largest ever studies on the link between reproductive factors and the disease, published in the British Journal of Cancer.


The research confirms the writings of Dr. Joel Brind, a world expert on the link between abortion and breast cancer, who noted that miscarriage does not lead to breast cancer as abortion does.

In the new study, researchers tracked women over a ten-year period, sending them detailed questionnaires and recording both reproductive factors and whether or not they developed breast cancer. Pre-menopausal and postmenopausal women were studied separately, in order to find out whether reproductive factors affected the two groups differently.

Of the 91,000 women in the study, 1,718 were diagnosed with breast cancer over the time period. Previous research on miscarriage had produced conflicting results, with some smaller studies suggesting that it might increase the risk of the disease. But the new, large-scale research found no evidence that women with a history of miscarriage were at higher risk of breast cancer in either the pre-menopausal or postmenopausal group.


Dr. Joel Brind, President of the Breast Cancer Prevention Institute and Professor of human biology and endocrinology Baruch College, explained the reason for the increased risk of breast cancer with abortion and lack thereof with miscarriage in a 1997 paper entitled The Estrogen Connection.

Dr. Brind wrote, "pregnancies destined to abort spontaneously (i.e., end in miscarriage) during the first trimester usually do not generate estradiol in quantities exceeding non-pregnant levels." He explains that estradiol, which causes the breasts to grow during pregnancy makes for more undifferentiated cells – the same cells which are vulnerable to cancer – and thus with induced abortions, as opposed to miscarriage, there is a greater vulnerability to breast cancer.

"Full term pregnancy," says Dr. Brind, "results in full differentiation of the breast tissue for the purpose of milk production, which leaves fewer cancer-vulnerable cells in the breasts than were there before the pregnancy began. This translates into the well known breast cancer risk lowering effect of a full term pregnancy."

LONDON, February 14, 2002 (

See a pdf version of Dr Clavel-Chapelon's study:

See Dr. Brind's paper on The Estrogen Connection: