title: Assessment of mammographic density before and after first full-term pregnancy.
abstract: Mammographic density (MD) has consistently been found as one of the strongest breast cancer risk factors. In our study, both qualitative and quantitative density measurements were performed in a hospital-based group of premenopausal women before and after first full-term pregnancy providing an opportunity for direct evaluation of the effects of one pregnancy on MD. Mammograms were obtained from 23 women before and after first full-term pregnancy and from 28 nulliparous controls. MD was determined by a standard qualitative assessment method using the Breast Imaging Reporting and Data System, and a quantitative computer-based threshold method (0-100%). The mean age at mammography before and after pregnancy was 31 and 34 years, respectively, with a mean difference of 40 months between mammographies. The quantitative density assessment showed a significant reduction in relative MD after pregnancy of 12 percentage points (8.6-15.4), compared with 3.1 (0.0-6.2) in the nulliparous control group (P<0.001). A reduction in MD of more than 10% was seen in 52% of the patients, compared with 18% of the controls. The qualitative density assessment confirmed a reduction in MD after pregnancy by one Breast Imaging Reporting and Data System category (P=0.02). This longitudinal study showed that MD can be influenced by one full-term pregnancy. This effect was seen with both quantitative and qualitative assessment methods. It may be hypothesized that breast cancer risk reduction associated with pregnancy is mediated through a direct reduction of MD, and MD assessment might be incorporated in individualizing risk assessment and prevention.
authors.affiliation: Department of Obstetrics and Gynecology, University Breast Center Franconia, Erlangen, Germany.
authors.forename: Christian R
authors.initials: CR
authors.lastname: Loehberg
authors.forename: Katharina
authors.initials: K
authors.lastname: Heusinger
authors.forename: Sebastian M
authors.initials: SM
authors.lastname: Jud
authors.forename: Lothar
authors.initials: L
authors.lastname: Haeberle
authors.forename: Alexander
authors.initials: A
authors.lastname: Hein
authors.forename: Claudia
authors.initials: C
authors.lastname: Rauh
authors.forename: Mayada R
authors.initials: MR
authors.lastname: Bani
authors.forename: Michael P
authors.initials: MP
authors.lastname: Lux
authors.forename: Michael G
authors.initials: MG
authors.lastname: Schrauder
authors.forename: Christian M
authors.initials: CM
authors.lastname: Bayer
authors.forename: Cosima
authors.initials: C
authors.lastname: Helbig
authors.forename: Ronald
authors.initials: R
authors.lastname: Grolik
authors.forename: Boris
authors.initials: B
authors.lastname: Adamietz
authors.forename: Ruediger
authors.initials: R
authors.lastname: Schulz-Wendtland
authors.forename: Matthias W
authors.initials: MW
authors.lastname: Beckmann
authors.forename: Peter A
authors.initials: PA
authors.lastname: Fasching
mesh_terms: D000328:Adult; D001940:Breast / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008327:Mammography; D010298:Parity; D011247:Pregnancy / Q000502:physiology*; D012307:Risk Factors; D047929:Term Birth; D013997:Time Factors