A Woman Performing a Breast Self-Exam (image) NIH/National Institute of Environmental Health Sciences Share Print E-Mail Caption The study suggests breast cancer protection from pregnancy may not begin until as many as 30 years after the last pregnancy. Credit NIEHS Usage Restrictions For use with media coverage of this press release only. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.