An international study of nearly 400,000 women has found that breast self-exams may do more harm than good. Women who poke and prod their own breasts to look for lumps rarely find cancer early enough to save their lives; most of the time, these examinations lead to false alarms and painful biopsies. Researchers trained hundreds of thousands of Russian and Chinese women to do regular self-checks for breast lumps. They also included a control group of women who didn’t do the self-exams. Of the 587 women who died of breast cancer over the course of the study, 292 had been performing self-exams, while the other 295 hadn’t—a statistically insignificant difference. The women who did do the self-exams underwent twice the number of biopsies, and also had several shaky weeks of panic. Researchers said that women who do find breast lumps should, of course, immediately contact a doctor. “Our recommendation is that women who want to do a breast self-exam should go ahead and do it as long as they realize the limitations and that there may be extra biopsies,” Debbie Saslow of the American Cancer Society tells Time. But “women who don’t want to do breast self-exams shouldn’t feel guilty about it.”