The Czech tested positive for trimetazidine, which is prohibited under the Tennis Anti-Doping Programme, in February and again in March, according to a statement.
Trimetazidine is a metabolic modulator sometimes used as heart medication and Bartunkova, who reached a career-high 226 in the WTA rankings in April, did not have a Therapeutic Use Exemption (TUE).
Bartunkova was beaten by beaten by American Clervie Ngounoue (17) in last year's Wimbledon juniors final.
