Taking ibuprofen does not delay menstruation. Ibuprofen is a painkiller. It works by inhibiting the synthesis of prostaglandins to improve the mediators of the nervous system and provide pain relief. Ibuprofen reduces the contraction and spasm of smooth muscles, relieves pain and does not cause menstrual disorders or delay menstruation. Delayed menstruation is generally more common clinically, like irregular menstruation may affect delayed menstruation. The delayed menstruation should be ruled out first of all for pregnancy, while ovarian dysfunction, mental tension and overexertion can all cause delayed menstruation.