Breast Tenderness Before Your Period? New Study Confirms It’s a Normal Sign of Healthy Ovulation

If you experience mild breast tenderness or swelling before your period, you're far from alone—and new research shows it may actually be a sign of a healthy, ovulatory cycle.

A year-long study led by researchers at the University of British Columbia tracked 53 healthy, menstruating women aged 20 to 41, each with regular cycles ranging from 21 to 36 days. The results offer new insights into how common breast symptoms are linked to ovulation—and why that matters for your long-term health.

What the Research Found

According to the study, published in PLOS One, most participants experienced mild breast tenderness and swelling in the days leading up to menstruation—but only when ovulation occurred normally. This suggests that these symptoms are not necessarily signs of something being "wrong," but instead part of a typical, healthy menstrual cycle.

“Previous research hasn’t clearly established whether these breast changes are part of premenstrual syndrome (PMS) and therefore problematic, or just expected physiological responses,” explained Dr. Azita Goshtasebi, a family physician and co-author of the study.

Tracking the Menstrual Cycle—In Detail

Participants recorded their daily experiences using a Menstrual Cycle Diary©, noting breast changes such as tenderness and size fluctuations. Researchers confirmed ovulation using a validated Quantitative Basal Temperature© method, which tracks subtle temperature shifts to identify when an egg has been released.

Across more than 694 menstrual cycles, researchers found that:

• 71% were normally ovulatory cycles

• 26% had short luteal phases (less than 10 days, which may indicate hormone imbalances)

• 3% were anovulatory (no ovulation occurred)

The median level of breast tenderness (on a 0–4 scale) was 1.4, and changes in breast size (on a 1–5 scale, where 3 means no change) averaged a rating of 4—indicating noticeable but not extreme changes.

“This is the first long-term study to link breast symptoms with confirmed ovulation,” said lead author Dr. Mary Wood, who began the research as a medical student and is now an internal medicine resident. “We were surprised to find that breast tenderness and swelling were more common when ovulation was healthy and regular.”

Why This Matters

These findings have broader implications than just tracking your PMS symptoms. According to Dr. Jerilynn C. Prior, principal investigator of the study and a leading voice in ovulatory health, understanding the body’s normal responses is essential in identifying subtle ovulation disturbances—even in women with seemingly “normal” cycles.

“Many women can have regular-length cycles but still experience recurring ovulatory issues, which may lead to health consequences like bone loss or increased cardiovascular risk down the line,” she explained.

By linking breast symptoms to ovulation status, the research team hopes to offer a non-invasive clue into a woman’s hormonal health—something that could help both clinicians and individuals better understand what's going on inside their bodies.

The Big Takeaway

Breast tenderness and swelling before your period aren’t necessarily signs of PMS gone rogue. In fact, they may be indicators that your body is ovulating as it should. But, as always, if symptoms feel severe or disruptive, it’s worth talking to a healthcare provider.

This study marks a step forward in demystifying the female hormonal cycle—and reinforces the importance of listening to your body, tracking your symptoms, and recognising what’s truly normal.

Study Reference: Wood, M., et al. (2025). Breast tenderness and swelling experiences related to menstrual cycles and ovulation in healthy premenopausal women: Secondary analysis of the 1-year “Prospective Ovulation Cohort.” PLOS One. doi.org/10.1371/journal.pone.0321205.