EP1346 - ECE_2904 - Hyperprolactinemia in Polycystic Ovary Syndrome: clinical and biochemical differences from normoprolactinemic PCOS

Abstract

Polycystic ovary syndrome(PCOS) is a prevalent endocrine disorder characterized by hyperandrogenism and ovulatory dysfunction. Although mild hyperprolactinemia is frequently reported in PCOS, its clinical relevance and contribution to hyperandrogenism remain uncertain. To compare the clinical, hormonal, and metabolic characteristics of hyperprolactinemic and normoprolactinemic women with PCOS and to evaluate the independent association between prolactin levels and hyperandrogenemia. This retrospective observational study included 372 women aged 18-40 years diagnosed with PCOS according to the Rotterdam criteria between 2018 and 2025. Patients were classified as hyperprolactinemic (n = 133) or normoprolactinemic (n = 239) based on baseline serum prolactin levels, after exclusion of secondary causes of hyperprolactinemia. Clinical features, hormonal profiles, and metabolic parameters were compared between groups. Correlations between prolactin and hormonal variables were assessed using Spearman's analysis. Multivariable linear regression was performed to identify independent predictors of total testosterone levels. Hyperprolactinemic PCOS patients exhibited significantly higher LH/FSH ratios, total testosterone, DHEAS, and TSH levels compared with normoprolactinemic patients (all P < .05), while age, estradiol, metabolic parameters, lipid profiles, and the prevalence of hirsutism, acne, and menstrual irregularities were similar between groups. Prolactin levels showed positive correlations with total testosterone (r = 0.246), DHEAS (r = 0.182), and TSH (r = 0.196) (all P ≤ .001). In multivariable regression analysis, prolactin (B = 0.003, P = .001), LH/FSH ratio (B = 0.045, P < .001), and HOMA-IR (B = 0.008, P = .029) were independently associated with higher total testosterone levels, whereas TSH and age were not(Table 1). Mild hyperprolactinemia in PCOS is associated with a more pronounced hyperandrogenic hormonal profile, independent of insulin resistance and age. These findings support a potential contributory role of prolactin in PCOS-related hyperandrogenism and suggest that hyperprolactinemic PCOS may represent a distinct endocrine phenotype warranting further prospective investigation.Table 1Multivariable linear regression analysis for total testosterone.VariableBStandardized β95% CI (Lower)95% CI (Upper)P valueProlactin (ng/mL)0.0030.1830.0010.005.001LH/FSH ratio0.0450.2540.0270.064<.001HOMA-IR0.0080.1170.0010.015.029TSH (mIU/L)0.0130.047−0.0160.043.378Age (years)−0.004−0.086−0.0090.001.108B indicates unstandardized regression coefficients; β indicates standardized coefficients; CI, confidence interval. The coefficient of determination was R2 = 0.144 and adjusted R2 = 0.131. No multicollinearity was detected.