Many menstrual problems may be symptoms of undiagnosed thyroid conditions. Girls who have either very early or very late menstruation should be evaluated for a potential thyroid problem, as thyroid problems can frequently be a cause of early or delayed puberty and menstruation. In addition, any change in menstrual patterns – such as more or less frequent periods, the onset of substantially heavier or lighter periods, or the lack of periods entirely, should trigger a thyroid evaluation by your physician.

Thyroid disease is frequently the reason behind problems with a woman’s menstrual cycle.

Early Menstruation/ Precocious Puberty: Hypothyroidism in girls may trigger very early menstruation, i.e., before the age of 10. This early puberty is known as “precocious puberty”. Occasionally, if hyperthyroidism occurs very early during puberty, menstrual periods may also begin earlier than usual.

Late Menstruation/ Delayed Puberty: Hyperthyroidism in a teenage girl can delay the onset of puberty and onset of menstruation into the mid-teens, in some cases after the age of 15.

Lighter Periods: Lighter than normal periods are frequently associated with hyperthyroidism.

Infrequent or Sporadic Periods: Infrequent or sporadic periods are frequently associated with hyperthyroidism.

Absent Periods/ Amenorrhea: Hyperthyroidism can cause menstruation to stop for longer periods, a condition known as amenorrhea.

Heavy Periods/ Menorrhagia: Menorrhagia is defined as excessively heavy or prolonged menstrual bleeding, for example, soaking through pad every hour for several hours. Hypothyroidism is associated with menorrhagia.

More Frequent, Longer Periods: Hypothyroidism is known to cause periods to come more frequently – for example, some women will find their 28 day cycle shortens to a 25 day cycle, and their normally 5-day long menses lasts 6 or 7 days.

Painful Menstruation, Dysmenorrhea: Hypothyroidism is associated with painful menstrual periods, known as dysmenorrhea. Dysmenorrhea can include an achy or stabbing low backache, nausea, leg aches, feelings of fullness, headaches, and bowel disturbances.
When to See the Thyroid specialist

  • If heavy bleeding lasts for over 24 hours
  • If your period regularly lasts more than seven days
  • If periods are coming less than 21 days apart
  • If periods have stopped for more than three months
  • If periods are accompanied by much greater level of pain than usual


Key Steps
Even when considered treated for hypothyroidism or hyperthyroidism, some women still report that menstrual symptoms continue.

If you are hypothyroid, be sure that you are optimally treated, as symptoms such as menstrual problems may persist if you are not at the optimal TSH and on the proper thyroid drug for you.

Women who are having menstrual irregularities should have their doctor conduct a thorough hormonal evaluation at several points in their cycle, looking at estrogen, progesterone, follicle stimulating hormone, and luteinizing hormone levels, among others, to evaluate whether the hormonal cycle is normal. Significant irregularities in hormonal levels may warrant hormone treatment, or may warrant further evaluation and diagnosis.