PROCESS FOR PRODUCING A PHARMACEUTICAL PREPARATION FOR THERAPEUTIC TREATMENT OF ENDOMETRIOSIS CONTAINING A COMBINATION OF A GESTAGEN AND (6S)-5-METHYLTETRAHYDROFOLATE

A combination of an anti-androgenic gestagen at a daily dose of from an ovulation-inhibiting dose up to at most twice the ovulation-inhibiting dose and from 0.1 to 10 mg of (6S)-5-methyltetrahydrofolate are used to produce a pharmaceutical preparation for therapeutically treating endometriosis while simultaneously reducing therapy side effects including the negative effect on bone density and/or bone metabolism, reducing the risk of osteoporosis and, in the event of pregnancy, reducing the risk of congenital malformations, such as medullary tube defects, cleft lip, cleft jaw, or cleft palate, and the risk of pregnancy complications, such as detachment of the placenta and premature birth. The preparation is suitable for long-term administration, which continues daily for at least 169 days to at least two years.