Fibroids, thyroid conditions, and abnormal bleeding

Fibroids are non-cancerous growths in or around the uterus. Many people never notice them, but for others they cause heavy bleeding, pelvic pressure, or pain during sex. Thyroid conditions, both an underactive and an overactive thyroid, can affect cycle regularity, weight, energy, and mood, because the thyroid gland influences hormone levels throughout the body. Both are common reasons women in their twenties and thirties end up with unexplained pain, heavy periods, or fatigue, and both can take years to get diagnosed because the early symptoms look like things people are told to just live with.

A typical cycle runs somewhere between 21 and 35 days, with bleeding lasting around two to seven days. Abnormal uterine bleeding covers anything that falls well outside that: periods that come much more or less often than that range, bleeding between periods, or a period heavy enough to soak through a pad or tampon in an hour or less for several consecutive hours. Fibroids and thyroid conditions are two of the more common causes, alongside PCOS and certain medications, but the bleeding pattern itself does not point to a specific cause, which is exactly why it is worth evaluating rather than guessing about.

A pattern worth paying attention to is pain that keeps you from your normal activities, bleeding that soaks through protection faster than expected, or fatigue that does not improve with rest. A useful habit is tracking cycle length, how many days bleeding lasts, and roughly how heavy it is, rather than relying on memory when a clinician asks. "It has been heavier lately" is harder to act on than "I have soaked through protection hourly for the last two cycles."

None of this is a diagnosis, and only a clinician can tell you what is actually going on. If bleeding is heavy enough to cause dizziness, or soaks through protection every hour for more than a couple of hours, that is a same-day medical concern, not something to wait out. Otherwise, tracking what you notice over a few cycles, rather than just remembering the worst month, gives a doctor something concrete to work with.