“Proceedings were held on Wednesday at the Court of Cassation, which will issue a ruling on February 28,” a judicial source said on Wednesday.
Amadou was prime minister from 1995-6 and 2000-2007, and president of the national assembly from 2011 to 2014. He stood against President Mahamadou Issoufou in elections in 2016 but flew to France before the second round of voting.
In a case that has poisoned the political climate for more than two years, Amadou is one of about 20 people accused of smuggling babies from Nigeria via Benin to wealthy couples in Niger.
They include a former minister, bankers, businessmen an army officer and their spouses.
He had initially been charged for “complicity” in the alleged trafficking, but the charge was changed on the judge’s orders to that of “illicitly dealing in children”. He was tried in absentia and convicted last March.
Amadou maintains the charges against him are politically motivated.
One of his wives, Hadiza Hama Amadou, who was handed a one-year sentence, was released in December after serving her term, her relatives said.
Nicknamed “the Phoenix” for his political comebacks, Amadou was arrested in November 2015 on a return from exile. His campaign for the presidency had to be conducted from behind bars.
He was released on medical grounds on March 16, 2016, four days before the second round of voting, and flew to France.
Issoufou went on to win with 92 percent of the run-off ballot in the 2016 vote. With the opposition boycotting the election, Amadou only got seven percent of the vote.