Constantin (as Mitica Junghiatu) won silver in the 800 metres behind Slobodanka Colovic, and bronze in the 1500m behind Paula Ivan and Svetlana Kitova at the 1987 Summer Universiade in Zagreb. She also reached the 800 metres final at the 1986 European Championships, and both the 800m and 1500m finals at the 1987 World Championships. In 1989, now competing under her married name, Constantin finished fifth in the 1500m final at the World Indoor Championships.