Heavy or Irregular Periods

Hypothyroidism is associated with both irregular and excessive menstrual flow. According to one study, around 40% of women with low thyroid hormone had increased monthly irregularity or excessive bleeding in the previous year, compared to 26% of women with normal thyroid levels. Another study found that 30% of hypothyroid women had irregular and heavy menstruation. These women were identified with hypothyroidism after being checked for other symptoms.

Thyroid hormone interacts with other hormones that regulate the menstrual cycle, and high amounts of it can interfere with their signals. The thyroid hormone also has an effect on the ovaries and uterus. Aside from hypothyroidism, there are numerous other conditions that might produce heavy or irregular periods. If you have irregular or heavy periods that interfere with your daily life, consult a gynecologist before worrying about your thyroid.