The case reported consists of thrombosis of the left internal jugular vein occuring on the 22nd week of amenorrhea of a pregnancy achieved by IVF No etiological factor other than biochemical ovarian hyperstimulation was found. Maternal outcome was positive but intrauterine fetal death occured 7 weeks later at 29 weeks of amenorrhea. The late occurence of this thrombosis after ovarian hyperstimulation need to be stressed.