Jansen won the first of her three consecutive Dutch national titles in the 1977–78 season. A competitor at five ISU Championships, she finished 17th at the 1978 Europeans in Strasbourg, France; 18th at the 1978 Worlds in Ottawa, Ontario, Canada; 20th at the 1979 Europeans in Zagreb, Yugoslavia; 23rd at the 1979 Worlds in Vienna, Austria; and 18th at the 1980 Europeans in Gothenburg, Sweden.