The AIU, which oversees integrity issues in athletics, including doping, posted documents from the Court Arbitration for Sport (CAS) that said the ban was based on the fact Ponomareva had abnormalities in her biological passport.
The CAS documents said Ponomareva had used doping for "a period of more than two years."
Her four-year suspension comes into force as of March 8, 2018, and her results between July 2015 and March 2018 are voided, the CAS documents said.
Russia's athletics federation has been suspended since a 2015 report commissioned by the World Anti-Doping Agency (WADA) found evidence of state-sponsored doping in the sport.
The sport's global governing body, the International Association of Athletics Federation (IAAF), earlier this month decided not to lift Russia's suspension.
Despite the ban, the IAAF has authorised some Russians, including 2015 world champion hurdler Sergey Shubenkov, to compete as neutrals after having demonstrated they are competing in a doping-free environment.
(Reporting by Gabrielle Tétrault-Farber; Editing by Ken Ferris)
