After 24 months of DNG treatment, the mean uterine volume marginally dropped from 157.9 to 153.3 ml (p > .05). All laboratory measurements fell within the expected range. As a long-term treatment for symptomatic adenomyosis, DNG is efficient and well tolerated. It can also be used as maintenance therapy following the cessation of GnRH-a administration. This evidence concerns the gene GNRH1 and adenomyosis.