The present invention relates to novel pyrrolidine derivative of formula (I), its geometrical isomers, its optically active forms as enantiomers, diastereomers, mixtures of these and its racemate forms, as well as salts thereof, wherein R.sup.1 is selected from the group comprising or consisting of H and C.sub.1 C.sub.6-alkyl, for the prevention and/or treatment of preterm labor, premature birth or dysmenorrhea ##STR00001##