The present invention relates to solid oral unit dosage form, in particular to oral contraceptives, comprising i) granules comprising a progestogen, such as drospirenone; an estrogen, such as ethinylestradiol; and microcrystalline cellulose and, ii) a pharmaceutically acceptable salt of 5-methyl-(6S)-tetrahydrofolic acid. 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.