European Journal of Endocrinology

 Combined oral contraceptives plus spironolactone compared with metformin in women with polycystic ovary syndrome: a one-year randomized clinical trial

We aimed to compare a combined oral contraceptive (COC) plus the antiandrogen spironolactone with the insulin sensitizer metformin in women with polycystic ovary syndrome (PCOS).


We conducted a randomized, parallel, open-label, clinical trial comparing COC (30 μg of ethinylestradiol and 150 μg of desogestrel) plus spironolactone (100 mg/day) with metformin (850 mg b.i.d.) for one year in women with PCOS (EudraCT2008–004531–38).


The composite primary outcome included efficacy (amelioration of hirsutism, androgen excess and menstrual dysfunction) and cardiometabolic safety (changes in the frequencies of disorders of glucose tolerance, dyslipidemia and hypertension). A complete anthropometric, biochemical, hormonal and metabolic evaluation was conducted every three months and data were submitted to intention-to-treat analyses.


Twenty-four patients were assigned to COC plus spironolactone and 22 patients to metformin. Compared with metformin, COC plus spironolactone caused larger decreases in hirsutism score (mean difference 4.6 points, 95% CI: 2.6–6.7), total testosterone (1.1 nmol/L, 0.4–1.7), free testosterone (25 pmol/L, 12–39), androstenedione (5.5 nmol/L, 1.8–9.2) and dehydroepiandrosterone sulfate (2.7 μmol/L, 1.4–4.0). Menstrual dysfunction was less frequent with COC plus spironolactone (OR: 0.06, 95% CI: 0.02–0.23). No differences were found in frequencies of abnormal glucose tolerance (OR: 1.7, 95% CI: 0.7–4.4), dyslipidemia (OR: 0.6, 95% CI: 0.2–1.8) or hypertension (OR: 0.3, 95% CI: 0.5–2.0). No major adverse events occurred and biochemical markers were similarly safe with both treatments.


COC plus spironolactone was more effective than metformin for symptoms of PCOS showing similar safety and overall neutral effects on cardiometabolic risk factors.