Women with breast cancer do not face a greater risk of death if they become pregnant, according to a study.
The study of Danish women, in the British medical journal The Lancet, found no statistically significant difference in the risk of death compared to breast cancer patients who did not become pregnant.
The study was directed by Dr. Niels Kroman of the Danish Epidemiology Science Center.
Dr. Eugenia Calle, director of nalytic epidemiology at the American Cancer Society in Atlanta, said that previous studies had not found an increased risk. But those studies were unable to discount the possibility that only women with smaller or less-advanced cancers were taking the risk of becoming pregnant.
While no single study is conclusive, she said this one would be helpful for doctors advising breast-cancer patients who are considering pregnancy.
“It’s a very nicely done study, very careful. It looks like they were able to do what some of the previous studies were not able to do,” Calle said.
The issue has been difficult to study because breast cancer tends to develop later in life, after childbearing years.
That was evident in this study, which involved 5,725 Danish women age 45 or younger who had been diagnosed with breast cancer. Of those, 173 became pregnant after diagnosis. Eighty-four had a full-term pregnancy, 77 had induced abortion, and 12 miscarried.
The women who became pregnant had a slightly lower death rate than those who did not, though the authors said the difference was too small to be statistically significant.