Is there association between thyroid stimulating hormone levels and the four phenotypes in polycystic ovary syndrome?

The aim of this study was to determine whether the incidence of subclinical hypothyroidism (SCH) is higher in polycystic ovary syndrome (PCOS) group than the control group. Additionally, the study investigated whether serum thyroid stimulating hormone (TSH) level is associated with various clinical parameters of PCOS regarding different phenotypes of the disease.

This retrospective, case-control study included 329 PCOS patients and 162 control women who were aged between 20 and 42 years and visited the Gynecology outpatient clinic in Pusan National University Hospital from January 2014 to December 2017. PCOS patients were further classified according to their phenotypes: phenotype A as the combination of all hyperandrogenism (HA), ovulatory dysfunction (OD), and polycystic ovarian morphology (PCOM); phenotype B as the combination of HA and OD; phenotype C as the combination of HA and PCOM; and finally, phenotype D as the combination of OD and PCOM. Laboratory blood tests included follicle stimulating hormone (FSH), luteinizing hormone (LH), TSH and anti-mullerian hormone (AMH). The ovarian volume was calculated using three diameters by gynecologic ultrasonography.

Serum TSH level was significantly higher in PCOS patients than in the control group after adjusting for age and body mass index (BMI). Serum TSH level was not related to HA and OD, but its significant association with PCOM was confirmed in comparative analysis in quartiles. The proportion of phenotype A patients increased as serum TSH level increased, while the proportion of phenotype B and D decreased. Phenotype C stayed relatively consistent with varying TSH levels.

More numbers of patients showed elevated TSH level satisfying SCH diagnosis in PCOS group than the control group. In addition, a significant correlation between serum TSH level and different PCOS phenotypes has been observed; especially, PCOS patients with phenotype A, which displays all of HA, OD, and PCOM, tended to have the higher TSH levels than the PCOS patients with other phenotypes, requiring proper and thorough evaluation for potential endocrine disparity and according to management in such patient group.