High prevalence of autoimmune thyroiditis in patients with polycystic ovary syndrome

Eur J Endocrinol. 2004 Mar;150(3):363-9. doi: 10.1530/eje.0.1500363.


Objective: To investigate the prevalence of autoimmune thyroiditis (AIT) in patients with polycystic ovary syndrome (PCOS).

Design: Over a period of 30 months, 175 patients with PCOS were recruited to a prospective multicenter study to evaluate thyroid function and morphology; 168 age-matched women without PCOS were studied as a control group.

Methods: PCOS was defined as a- or oligomenorrhea, hyperandrogenism and exclusion of other disturbances of estrogen or androgen synthesis. All laboratory parameters were determined with automated immunoassays. Thyroid morphology was assessed by ultrasound.

Results: PCOS patients were characterized by an increased LH/FSH ratio, low progesterone, elevated testosterone and a high prevalence of hirsutism (PCOS 83%, control 3%; mean hirsutism score 12+/-5 and 3+/-2 respectively), but no differences in estrogen levels were found. Thyroid function and thyroid-specific antibody tests revealed elevated thyroperoxidase (TPO) or thyroglobulin (TG) antibodies in 14 of 168 controls (8.3%), and in 47 of 175 patients with PCOS (26.9%; P<0.001). On thyroid ultrasound, 42.3% of PCOS patients, but only 6.5% of the controls (P<0.001) had a hypoechoic tissue typical of AIT; while thyroid hormone levels were normal in all subjects, PCOS patients had a higher mean TSH level (P<0.001) and a higher incidence of TSH levels above the upper limit of normal (PCOS 10.9%, controls 1.8%; P<0.001).

Conclusion: This prospective study demonstrates a threefold higher prevalence of AIT in patients with PCOS, correlated in part with an increased estrogen-to-progesterone ratio and characterized by early manifestation of the disease.

Publication types

  • Multicenter Study

MeSH terms

  • Adult
  • Blood Glucose / metabolism
  • Estradiol / blood
  • Female
  • Follicle Stimulating Hormone / blood
  • Humans
  • Insulin / blood
  • Luteinizing Hormone / blood
  • Polycystic Ovary Syndrome / blood
  • Polycystic Ovary Syndrome / complications*
  • Progesterone / blood
  • Prospective Studies
  • Testosterone / blood
  • Thyroglobulin / metabolism
  • Thyroid Hormones / blood
  • Thyroiditis, Autoimmune / blood
  • Thyroiditis, Autoimmune / complications*
  • Thyroiditis, Autoimmune / diagnostic imaging
  • Thyrotropin / blood
  • Ultrasonography


  • Blood Glucose
  • Insulin
  • Thyroid Hormones
  • Testosterone
  • Progesterone
  • Estradiol
  • Luteinizing Hormone
  • Follicle Stimulating Hormone
  • Thyrotropin
  • Thyroglobulin