Career
She is the child of Mita Reljin, a basketball player and coach, and Vukosava Milanović-Reljin, a basketball player for Radnički and later, Partizan. She began with rhythmic gymnastics in 1977 at age 9, after a primary school friend, named Mira, did the same. At the time Milena was doing folk dancing but, she became enchanted with rhythmic gymnastics after watching one of her friend"s training sessions.
Milena"s first coach was Olivera Radosavljević at the Senjak Gymnastics Club.
Olivera"s daughter Jasna Tomin later took over younger gymnasts, including Milena. Her next coach was Nada Vučković-Pisić at the Gymnastics Club Partizan.
In 1981, she took the all-around gold at the Balkan championships and tied Bulgarian Anelia Ralenkova for silver on clubs. She competed twice at Olympic Games Los Angeles 1984 where she came 5th All-Around, and Seoul 1988 where she placed 9th All-Around.
Milena retired from the sport in 1989.
After her retirement she took up coaching at her old club Partizan, where she coached from 1990 until 2002. In 2003, she started her own Rhythmic Gymnastics Club, Ritam, which she is now the director and head coach for around 400 girls aged 4 to 13. Reljin has also been an international judge at two World and three European Championships, as well as other international tournaments.