Each finalist is allowed three throws in last round, with the top eight athletes after that point being given three further attempts.
Darya Pishchalnikova, Nadine Müller and Sandra Perković made it in their first attempt, while Yarelys Barrios hit the top qualifier 65.94 in her second throw after fouling the first.
Her third round throw was a Croatian national record 69.11, solidifying her hold on the gold medal.
It was later announced that Pishchalnikova tested positive for the anabolic steroid oxandrolone in the samples taken in May 2012.
In April 2013 she was banned by the Russian Athletics Federation for ten years, and her results from May 2012 were annulled, meaning she was set on track to lose her Olympic medal.