in medicine, ovarian vein syndrome is a rare (possibly not uncommon, certainly under-diagnosed) condition in which a dilated ovarian vein compresses the ureter (the tube that brings the urine from the kidney to the bladder). this causes chronic or colicky abdominal pain, back pain and/or pelvic pain. the pain can worsen on lying down or between ovulation and menstruation. there can also be an increased tendency towards urinary tract infection or pyelonephritis (kidney infection). the right ovarian vein is most commonly involved, although the disease can be left-sided or affect both sides. it is currently classified as a form of pelvic congestion syndrome.