<prompt> Cause of unilateral dysmenorrheaOne horn of malformed uterusEndometriosis with unilateral distributionSmall fibroid at the utero tubal junctionAll of the above  <response>: Causes of unilateral dysmenorrhea : One horn of malformed uterus Endometriosis with unilateral distribution Small fibroid at the utero - tubal junction. Ovarian dysmenorrhea Right ovarian vein syndrome Colonic or caecal spasm. REF : gynecology book of shaw 17th 