Mild breast tenderness and swelling found to be part of healthy menstrual cycles

A one-year study in healthy women who were also consistently cycling every 21-36 days and had normal ovulation, showed that it is usual to experience mild breast tenderness and swelling before the next period. Breast tenderness and swelling are common concerns associated with the menstrual cycle. However, little research previously has indicated how or if these breast symptoms are linked with ovulation.

"Previous research has not clarified if breast tenderness and swelling, that may be experienced before menstruation, are part of a 'premenstrual syndrome' (PMS) and thus a problem and abnormal, or are something that is to be expected," said Dr. Azita Goshtasebi, a family physician, and co-author who helped design the study.

"Our study evaluated the experiences of 53 healthy women over the course of a year and found that minimal breast swelling and breast tenderness usually occurred before flow in regular, ovulatory menstrual cycles," reported the lead researcher, Dr. Mary Wood. She began this work as a medical student and is currently an internal medicine resident at the University of British Columbia.

Dr. Sonia Shirin, co-author and UBC Centre for Menstrual Cycle and Ovulation research associate, explained: "Breast symptoms-including whether or not there was any breast tenderness and the breasts changed in size-were recorded daily in the Menstrual Cycle Diary©. Also, ovulation or egg release was confirmed using the validated Quantitative Basal Temperature© analysis in these community women over an average of 13 cycles each."

This is the first longitudinal study to characterize breast experiences with confirmed ovulation. We were surprised to find that women actually had more breast tenderness and swelling when they had normal ovulation, compared to ovulatory disturbed cycles with short luteal phases (<10 days) or anovulation (no ovulation)."

Dr. Jerilynn C. Prior, principal investigator

"These results are exciting because a better understanding of what are 'normal' or 'healthy' menstrual cycle experiences are critical in order to identify women with recurrent ovulatory disturbances even though their cycles are regular and of normal lengths," said Dr. Wood. "There are possible long-term health consequences associated with disturbed ovulation within normal cycles including bone loss and risk for earlier heart attacks."

"Note that the relationship of breast tenderness and swelling with normally ovulatory cycles was only possible to show when we examined the experiences of all 53 women in 491 ovulatory cycles versus the 199 with ovulatory disturbances. That disappeared when we studied only the 47 women who had 420 normally ovulatory and 199 ovulatory disturbed cycles," Dr. Shirin shared. "That may be because we had fewer normally ovulatory cycles."

This study included 53 women, ages 20-41, with menstrual cycle data from an average of 13 cycles each.

Results showed that the median breast tenderness on a 0-4 scale was 1.4, and the change in breast size from usual on a 1-5 scale, where three represents no change, was 4.

A total of 694 cycles had ovulation status documented by temperature analysis, of which 71 per cent were determined to be normally ovulatory; 26 per cent had short luteal phase lengths; and three per cent were anovulatory. Given the small number of anovulatory cycles recorded, unfortunately, the researchers were not able to analyze anovulatory cycle data directly.