MAMMOGRAPHIC APPEARANCE OF THE BREASTS DURING PREGNANCY AND LACTATION- FALSE ASSUMPTIONS

Rationale and Objectives. It is believed that pregnant and lactating w omen have dense breasts, thereby limiting the usefulness of mammograph y. To our knowledge, no reports have been published on this topic for nearly 4 decades. The purpose of our study was to determine whether th is assumption is accurate given currentstate-of-the-art mammography. M aterials and Methods. Mammograms of 18 women (six pregnant, seven lact ating and five who recently discontinued lactation) were examined and compared with their baseline (before pregnancy or lactation) mammogram s and with mammograms of 18 age-matched control subjects. Studies were scored for breast density according to the Breast Imaging Reporting a nd Data System and evaluated for change in density and size. Results. Three of the six pregnant women had unchanged breast density compared with baseline studies and had scattered fibroglandular or heterogeneou sly dense tissue. Of the three without baseline studies, one had extre mely dense, one had heterogeneously dense, and one had scattered fibro glandular tissue. All seven lactating women had either heterogeneously dense or extremely dense tissue. The breast tissue in four was unchan ged in density and increased in two; no baseline study was available f or the remaining patient. Seven studies in five women who had disconti nued lactation 1 week to 5 months prior to mammography showed no chang e in density compared with baseline. Conclusion. Pregnant and lactatin g women do not always have dense breasts, and mammography can be perfo rmed without substantial concern for the limitations of breast density . Mammography can be as useful in these women as it is in other women with breast signs and symptoms.