Pregnancy Anomalies May Lower Breast Cancer Risk
Certain abnormalities occurring in problem pregnancies are associated with a long-term reduction in risk of breast cancer, according to a study released on Tuesday that tracked women for four decades. Researchers led by epidemiologist Barbara Cohn of the Public Health Institute in Berkeley, California, examined records on 3,804 white women in the San Francisco area who were pregnant during the period from June 1959 through April 1967.
The study found that three anomalies — two relating to the placenta and one involving the women’s blood pressure — were linked with a big decline in breast cancer occurrence. Cohn said changes in the levels of hormones and other substances in the body caused by the abnormalities may produce a protective effect. She also noted that most of the women who experienced the anomalies still gave birth to healthy babies. "It’s more subtle than to say what’s bad for the baby is good for the mother. It’s really not quite like that. " Cohn said in a telephone interview.
She said she was hopeful that researchers could nail down the exact mechanisms at work in providing the long-term cancer protection for the women who experienced these complications. "It’s certainly possible that one might be able to design a treatment or possibly a prevention that is related to these factors. " Cohn said.
She said scientists have known for many years that events that occur in pregnancy have an impact on the risk of breast cancer. Cohn said her study provides new details about some specific characteristics of pregnancies that may relate to long-term protection against breast cancer.
A. blood pressure increase experienced by the mother between the second and third trimesters of the pregnancy was associated with lower breast cancer incidence, the study found. Women whose increase was in the highest 25 percent of population studied had a 51 percent reduction in breast cancer rate.
Women with a smaller placenta size ( weight and diameter) also had lower breast cancer rates. The placenta, the tissue that connects the mother and fetus, produces hormones to help maintain the pregnancy and allows the exchange of oxygen, nutrients and waste materials.
In addition, women who experienced a condition known as maternal floor infarction of the placenta — a serious abnormality that can block the flow of oxygen and nutrients to the fetus — had a 60 percent reduction in breast cancer rate.
All three risk factors in combination were linked with up to a 94 percent reduction in breast cancer incidence, the study concluded.
It seems that Cohn is ______ of finding out the exact mechanisms at work.