Featured Research

from universities, journals, and other organizations

Neither Abortion Nor Miscarriage Associated With Breast Cancer Risk

Date:
April 24, 2007
Source:
JAMA and Archives Journals
Summary:
Neither induced abortion nor spontaneous abortion (miscarriage) appears to be associated with breast cancer risk in premenopausal women, according to a recent report.

Neither induced abortion nor spontaneous abortion (miscarriage) appears to be associated with breast cancer risk in premenopausal women, according to a report in the April 23 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.

Women younger than age 35 who carry a pregnancy to term appear to have a reduced lifetime risk of breast cancer, according to background information in the article. Pregnancy may accelerate breast cell differentiation, the process by which cells take on specialized roles. "An incomplete pregnancy may not result in sufficient differentiation to counter the high levels of pregnancy hormones that may foster proliferation," the rapid growth and division typical of cancer cells, the authors write. "However, these biological mechanisms are uncertain, and a prematurely terminated pregnancy may not affect breast cancer risk at all."

Karin B. Michels, Sc.D., Ph.D., and colleagues at Brigham and Women's Hospital, Harvard Medical School and Harvard School of Public Health, Boston, examined the association between abortion and breast cancer in 105,716 women who were part of the Nurses' Health Study II (NHSII). The women were between age 29 and 46 at the beginning of the study in 1993. At that time, and again every two years through 2003, they answered questions about whether and at what age they had had miscarriages or induced abortions and provided information about breast cancer risk factors and diagnoses.

A total of 16,118 participants (15 percent) reported having a history of induced abortion and 21,753 (21 percent) had a history of spontaneous abortion. Between 1993 and 2003, 1,458 new cases of breast cancer occurred among the women. "In this cohort study of young women, we found no association between induced abortion and breast cancer incidence and a suggestion of an inverse association between spontaneous abortion and breast cancer incidence during 10 years of follow-up," the authors write.

"We observed associations in two subgroups, an association between induced abortion and progesterone receptor--negative breast cancer [cancer that does not respond to the hormone progesterone] and an inverse association between spontaneous abortion before the age of 20 years and breast cancer incidence," they continue. However, they caution that these secondary analyses are based on small numbers of women. "No obvious mechanisms can be provided for these subgroup findings; thus, chance has to be considered as a possible explanation."

A 2003 international expert panel convened by the National Cancer Institute reviewed and assessed research regarding reproductive events and the risk of breast cancer, and concluded that based on existing evidence, induced abortion is not associated with an increased risk of breast cancer. "The data from the NHSII provide further evidence of a lack of an important overall association between induced or spontaneous abortions and risk of breast cancer," the authors conclude. "Among this predominantly pre-menopausal population, neither induced nor spontaneous abortion was associated with the incidence of breast cancer."

The NHSII is supported by a Public Health Service grant from the National Cancer Institute, National Institutes of Health, U.S. Department of Health and Human Services.


Story Source:

The above story is based on materials provided by JAMA and Archives Journals. Note: Materials may be edited for content and length.


Cite This Page:

JAMA and Archives Journals. "Neither Abortion Nor Miscarriage Associated With Breast Cancer Risk." ScienceDaily. ScienceDaily, 24 April 2007. <www.sciencedaily.com/releases/2007/04/070423185607.htm>.
JAMA and Archives Journals. (2007, April 24). Neither Abortion Nor Miscarriage Associated With Breast Cancer Risk. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2007/04/070423185607.htm
JAMA and Archives Journals. "Neither Abortion Nor Miscarriage Associated With Breast Cancer Risk." ScienceDaily. www.sciencedaily.com/releases/2007/04/070423185607.htm (accessed July 25, 2014).

Share This




More Health & Medicine News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

New Painkiller Designed To Discourage Abuse: Will It Work?

New Painkiller Designed To Discourage Abuse: Will It Work?

Newsy (July 24, 2014) The FDA approved Targiniq ER on Wednesday, a painkiller designed to keep users from abusing it. Like any new medication, however, it has doubters. Video provided by Newsy
Powered by NewsLook.com
Doctor At Forefront Of Fighting Ebola Outbreak Gets Ebola

Doctor At Forefront Of Fighting Ebola Outbreak Gets Ebola

Newsy (July 24, 2014) Sheik Umar Khan has treated many of the people infected in the Ebola outbreak, and now he's become one of them. Video provided by Newsy
Powered by NewsLook.com
Condemned Man's US Execution Takes Nearly Two Hours

Condemned Man's US Execution Takes Nearly Two Hours

AFP (July 24, 2014) America's death penalty debate raged Thursday after it took nearly two hours for Arizona to execute a prisoner who lost a Supreme Court battle challenging the experimental lethal drug cocktail. Duration: 00:55 Video provided by AFP
Powered by NewsLook.com
Can Watching TV Make You Feel Like A Failure?

Can Watching TV Make You Feel Like A Failure?

Newsy (July 24, 2014) A study by German researchers claims watching TV while you're stressed out can make you feel guilty and like a failure. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile: iPhone Android Web
          Follow: Facebook Twitter Google+
          Subscribe: RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins