Metformintherapie bei polyzystischem Ovarsyndrom (PCOS)

Zusammenfassung

Das polyzystische Ovarsyndrom (PCOS) ist eine der häufigsten Ursachen für die weibliche Infertilität. Neben den typischen Symptomen wie Oligo-/Amenorrhö, Hyperandrogenämie und Adipositas werden auch periphere Insulinresistenz, gestörte Glukosetoleranz und Hyperlipidämie beobachtet. Die Hyperinsulinämie und Veränderungen im IGF/IGFBP-System (insulin-like growth factor/insulin-like growth factor binding protein) spielen in der Pathogenese des PCOS vermutlich eine wichtige Rolle. Insulin und IGF bewirken eine Stimulation der ovariellen Androgenproduktion.

Vor diesem pathogenetischen Hintergrund erscheint eine Behandlung des PCOS durch Verbesserung der metabolischen Situation durch orale Antidiabetika wie z. B. Metformin sinnvoll: Metformin erhöht die Insulinempfindlichkeit, reduziert aber auch die Glukoseaufnahme aus dem Darm und ebenso die hepatische Glukoneogenese. Beim PCOS bewirkt Metformin eine Zyklusregulierung mit deutlicher Steigerung der Ovulationsrate sowie eine Gewichtsreduktion bei meistens adipösen PCOS-Patientinnen. Des Weiteren kommt es unter der Therapie zu einer Reduktion des Testosteronspiegels und Besserung der Akne sowie des Hirsutismus. Im Rahmen der Sterilitätstherapie zeigt sich ein besseres Ansprechen auf die Clomiphen- und FSH-Stimulation mit einer Erhöhung der Schwangerschaftsraten. Erste Studien zeigen auch einen positiven Effekt in der Frühschwangerschaft mit einer Reduktion der Fehlgeburtenrate, wobei es hier noch weiterer Untersuchungen bedarf. Die Metformineinnahme sollte in der Therapie des PCOS über mindestens 3 Monate erfolgen. Die Dosierung beträgt 3 × 500 mg, bzw. 2 × 850 mg. Prinzipiell ist die Metformintherapie bei adipösen PCOS-Patientinnen mit abdominalem Fettverteilungsmuster und peripherer Insulinresistenz indiziert, wobei auch die schlanken PCOS-Patientinnen von der Therapie profitieren können.

Abstract

The polycystic ovary syndrome (PCOS) is a common reason for female subfertility. Apart from the cardinal symptoms of irregular menstrual bleeding, hyperandrogenism and obesity, many women with PCOS have insulin resistance, impaired glucose tolerance and hyperlipidemia. Hyperinsulinemia and changes in insulin-like growth factor (IGF) and its binding protein appear to be central in the pathogenesis of PCOS. Both insulin and IGF indirectly stimulate ovarian synthesis of androgens. This suggests using antidiabetic agents to treat women with PCOS. Metformin increases insulin sensitivity, reduces glucose uptake and inhibits hepatic glucose synthesis. In obese women metformin promotes weight loss, improves menstrual control and increases ovuation rates. With metformin treatment, testosterone levels decrease and acne and hirsism improve. For ovarian stimulation, metformin improves the response to clomiphene or FSH, with increased pregancy rates. Some studies suggest reduced rates of pregnancy loss with metformin in early pregnancy. Metformin seems appropriate particularly for obese PCOS patients with peripheral insulin resistance. The recommended dosage is 500 mg tid or 850 mg bid for at least 3 months.

Schlüsselwörter

PCOS - Hyperandrogenämie - IGF - Hyperinsulinämie - Metformin - Sterilitätstherapie

Key words

PCOS - hyperandrogenemia - IGF - hyperinsulinemia - metformin infertility

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