Systematic Review Gynecol Obstet Invest 2018;83:105–115 Subclinical Hypothyroidism Impact on the Characteristics of Patients with Polycystic Ovary Syndrome. A Meta-Analysis of Observational Studies Sebastião Freitas de Medeiros a, b Matheus Antônio Souto de Medeiros b Cinthia Marenza Ormond b Jacklyne Silva Barbosa b Márcia Marly Winck Yamamoto b a Department of Gynecology and Obstetrics, Medical School, Federal University of Mato Grosso, Mato Grosso, Brazil; b Tropical Institute of Reproductive Medicine and Menopause, Cuiabá, Brazil Received: April 19, 2017 Accepted after revision: November 21, 2017 Published online: December 19, 2017 Sebastião Freitas de Medeiros Rua: Almirante Henrique Pinheiro Guedes, 195, Bairro: Duque de Caxias Cuiabá, MT CEP 78043-306 (Brazil) E-Mail de.medeiros @terra.com.br © 2017 S. Karger AG, Basel E-Mail karger@karger.com www.karger.com/goi DOI: 10.1159/000485619 Keywords Hyperandrogenism · Polycystic ovary syndrome · Subclinical hypothyroidism · Thyroid dysfunction Abstract Background/Aims: Definitive polycystic ovary syndrome (PCOS) diagnosis should exclude thyroid dysfunctions. The purpose of the study is to examine the impact of subclinical hypothyroidism on the characteristics of PCOS patients. Methods: A meta-analysis of the published observational studies was conducted. Medline, Scopus, and Cochrane da- tabase search was performed to identify the studies that compared euthyroid PCOS and subclinical hypothyroidism (SCH)-PCOS patients. A total of 9 studies were selected, total- izing the inclusion of 1,537 euthyroid PCOS and 301 SCH- PCOS. The data were expressed as raw mean difference and standard error, using the random-effects model. Heteroge- neity among studies was examined using the Cochran’s test (Q) and I 2 statistics. Results: Anthropometrical parameters were similar in both groups. Total cholesterol (TC) and tri- glyceride (TG) were higher in SCH-PCOS (p = 0.036 and p = 0.012). High-density lipoprotein cholesterol was lower in the SCH-PCOS group (p = 0.018). Fasting glucose was lower in euthyroid PCOS (p = 0.022). All androgen levels were similar in both group (p > 0.05 for all). Conclusion: TC, TG and fast- ing glucose were higher in SCH-PCOS patients. Because of the heterogeneity among studies, some summarized results should be interpreted with caution. Consistent data for fu- ture studies addressing PCOS diagnosis are provided. © 2017 S. Karger AG, Basel Introduction The most common clinical features of polycystic ova- ry syndrome (PCOS) include oligomenorrhea, amenor- rhea, infertility, hirsutism, weight gain, central obesity, and acanthosis nigricans. Hormonally, it can present el- evated luteinizing hormone (LH) levels with normal or slightly decreased levels of follicle-stimulating hor- mone, hyperandrogenemia, hyperinsulinemia, and nor- mal levels of cortisol (F), prolactin (PRL), thyroid-stim- ulating hormone (TSH), thyroxine (T4), and free thy- roxin (FT4) [1]. Low levels of sex hormone binding-globulin (SHBG) may represent a hyperinsu- linemic status. Dyslipidemia, dysglycemia, and insulin resistance, frequents in PCOS patients, increase the