Obese women with polycystic ovary syndrome (PCOS) exhibit similar metabolic characteristics as that of type 2 diabetes mellitus, in terms of increased resistance to insulin and hyperinsulinemia.^1,2 Since several decades, metformin has been used as an insulin sensitizer for the management of PCOS.¹ It is an effective ovulation induction agent for non-obese women with PCOS and offers some advantages over other first-line treatments such as clomiphene for anovulatory infertility.² Moreover, it is believed that metformin can improve endothelial function and dysfunction in women with PCOS.¹

Further, when compared to non-overweight women, overweight women with PCOS suffer more severe endocrine and metabolic disorders. Being overweight increases insulin secretion but weakens the metabolism of insulin secretion in the liver, fat, and skeletal muscle. In addition, it may also cause lipodystrophy and insulin resistance by reducing the expression of lipid droplet proteins in adipocytes. A systematic review involving 12 trials analysed the effects of metformin in overweight women with PCOS. The results showed significant changes in body mass index and waist circumference in the intervention group (with metformin intake) in comparison to the control group. Overall, it was observed that overweight women with PCOS treated with metformin had remarkably improved endocrine and metabolic indicators, including follicle-stimulating hormone, testosterone, luteinizing hormone, and low-density lipoprotein cholesterol. Thus, compared to control interventions, metformin seems to be an effective agent for overweight women with PCOS.¹

Current evidence-based guidelines also recommend use of metformin by overweight women with PCOS to control their weight and endocrine and metabolic disorders. This can be attributed to the beneficial effects of metformin like potential to reduce liver glucose production, inhibit gluconeogenesis and adipogenesis, and improve peripheral tissue insulin sensitivity. Besides, it can reduce weight, improve metabolic disorders and correct menstrual patterns, restore ovulation, and even allow conception.¹

Long-term treatment with metformin in women with PCOS, BMI ≥25 kg/m² and normal baseline glucose homeostasis also improved various parameters after the first year, like caused weight loss, increased menstrual regularity and improved androgen profile.³

Although most approved weight management drugs are contraindicated in women of reproductive age, metformin is considered a valuable therapeutic option with a favorable safety profile that can be used for treating PCOS in overweight women.¹

References

1. Guan Y, Wang D, Bu H, et al. The Effect of Metformin on Polycystic Ovary Syndrome in Overweight Women: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. International Journal of Endocrinology. 2020;2020:5150684.
2. Johnson NP. Metformin use in women with polycystic ovary syndrome. Ann Transl Med. 2014;2(6):56.
3. Jensterle M, Kravos NA, Ferjan S, et al. Long-term efficacy of metformin in overweight-obese PCOS: longitudinal follow-up of retrospective cohort. Endocrine Connections. 2020;9(1):44-54.