From the Guidelines
Low sex hormone binding globulin (SHBG) in the setting of oligomenorrhea is a significant indicator of polycystic ovary syndrome (PCOS) or insulin resistance, and initial management should focus on lifestyle modifications and hormonal regulation to improve insulin sensitivity and menstrual regularity. The significance of low SHBG in oligomenorrhea can be understood by examining the relationship between SHBG, insulin resistance, and PCOS.
- Low SHBG levels are often associated with insulin resistance, which is a key feature of PCOS 1.
- Insulin resistance leads to increased free testosterone levels, contributing to anovulation and oligomenorrhea.
- The study by Makolle et al. (2021) found that women with functional hypothalamic amenorrhea (FHA) and polycystic ovarian morphology (PCOM) had lower SHBG levels compared to those without PCOM 1. Some key management strategies for low SHBG in oligomenorrhea include:
- Lifestyle modifications such as weight loss, regular exercise, and a low-carbohydrate diet to improve insulin sensitivity.
- Hormonal regulation using combined hormonal contraceptives, such as ethinyl estradiol 20-35 mcg with a progestin, to regulate menstrual cycles.
- Metformin 500 mg once daily, increased gradually to 500-1000 mg twice daily, to improve insulin sensitivity and restore regular cycles.
- Ovulation induction with letrozole 2.5-7.5 mg daily for 5 days starting on cycle days 3-5 for those desiring pregnancy. It is essential to monitor metabolic parameters regularly in these patients, as they have an increased risk of developing type 2 diabetes and cardiovascular disease 1.
From the Research
Significance of Low SHBG in Oligomenorrhea
- Low Sex Hormone-Binding Globulin (SHBG) levels are associated with insulin resistance (IR), hyperandrogenemia, and abnormal glucose and lipid metabolism in women with polycystic ovary syndrome (PCOS) 2, 3, 4, 5, 6
- SHBG is a biomarker of metabolic abnormalities and is related to the long-term prognosis of PCOS 2, 4, 6
- Low serum SHBG levels increase the bioavailability of androgens, leading to progression of ovarian pathology, anovulation, and the phenotypic characteristics of PCOS 5
- SHBG gene polymorphism is correlated with the risk of PCOS, and therapeutic interventions can improve SHBG levels in PCOS women, reducing PCOS-associated complications 2, 4, 6
- The relationship between SHBG and oligomenorrhea is linked to the pathogenesis of PCOS, where low hepatic SHBG production may be a key step in the development of PCOS 5
Association with PCOS
- Low SHBG levels are considered a biomarker of abnormal metabolism and are associated with insulin resistance, compensatory hyperinsulinemia, and abnormalities in glucose and lipid metabolism in PCOS patients 2, 3, 4, 6
- SHBG is inversely associated with PCOS, obesity, insulin resistance, metabolic syndrome, and diabetes type II 4
- Therapeutic agents, such as metformin, glucagon-like peptide-1 receptor agonists, thiazolidinediones, compound oral contraceptives, and nutrient supplements, can regulate SHBG levels to ameliorate PCOS complications and improve prognosis 2