USE OF GESTAGENS IN COMBINATION WITH (6S)-5-METHYLTETRAHYDROFOLAT E FOR THE THERAPY OF ENDOMETRIOSIS WITH SIMULTANEOUS REDUCTION OF THERAPY SIDE EFFECTS AND THE REDUCTION OF THE RISK OF CONGENITAL MALFORMATIONS IN CASE OF PREGNANCY.

Antiandrogenic gestagens in a daily dosage unit, corresponding to no more than two times the dosage required to suppress ovulation, are used in combination with (6S)-5-methyltetrahydrofolate for the production of pharmaceutical preparations for the therapy of endometrioses with simultaneous reduction of therapy side effects, such as the negative impact on bone density/bone metabolism and the risk for osteoporosis, and in the event of pregnancy, the reduction of the risk on congenital malformations, such as neural tube defects, cheilognathopalatoschisis and complications during pregnancy, such as the detachment of the placenta and premature birth. The invention is suitable for long-term use.