University of Kentucky plastic surgeon Brian Rinker encountered many women in his practice who attributed their sagging breasts to breastfeeding, which was also the usual belief among medical practitioners. He decided to find out if this was true, and between 1998 and 2006 he and other researchers interviewed 132 women who were seeking breast augmentation or breast lifts. They studied the women's medical history, body mass index (BMI), their number of pregnancies, their breast cup size before pregnancy, and smoking status. The study results were presented at a conference of the American Society of Plastic Surgeons.