The present invention relates to solid pharmaceutical compositions, in particular to oral contraceptives, comprising a progestogen, such as drospirenone; an estrogen, such as ethinylestradiol; a tetrahydrofolic acid or a pharmaceutically acceptable salt thereof, such as calcium 5-methyl-(6S)-tetrahydrofolate; and at least one pharmaceutical acceptable excipient or carrier. The compositions of the invention provide good stability of the tetrahydrofolic acid upon storage while still ensuring a fast and reliable release of the estrogen and the progestogen present in the composition.