Suggest Treatment For Severe Menstrual Cramps

Hi my fiancae (age 26 yrs. ) is having menstrual periods and she is feeling so much pain in abdominal region... I asked her to take meftal spas but she told that her mother is refusing her to take such pills...? so my question is what to take when a girl suffers from menstrual pain what remedy? and if she takes pill like super spas or meftal spas what side effects they posses which may affect further sex life and whether they cause any problem to bear child?
Thank you :-)