Japanese prime minister's wife has revealed she went through fertility treatment and considered adoption but said she and Prime Minister Shinzo Abe have accepted they will have no children.

Japanese first lady Akie Abe, second left, receives a scroll with Chinese characters meaning peace and friendship, from student Zhang Shuo, right, during her visit to a junior high school in Beijing on Sunday October 8, 2006. [AP]

Akie Abe's remarks to a magazine were remarkably frank for a prime minister's wife, reflecting her effort to show a more human side of her husband, Japan's youngest post-World War II premier.

Shinzo Abe, 52, has pledged to encourage Japanese to have more children to reverse a declining birthrate, triggering media speculation as to why he is childless himself.

In an interview with the monthly magazine Bungei Shunju, Akie Abe, 44, confessed she felt strong pressure to bear children because her husband is a third-generation politician.

"Coming from a household of politicians, there was of course a lot of pressure, including from local constituents. But now it has become difficult, in part because of my age, so people no longer tell me to keep at it," she said.

"At the early stage, I did go through fertility treatment. But I think that I should accept my fate that I am the wife of a politician who became prime minister, and that we did not have the gift of having children."

She said she considered adopting a child a rare occurrence in Japan other than within extended families and noted that adoption was "very common in the United States."

Japan's Prime Minister Shinzo Abe (L) and first lady Akie Abe disembark from a plane at the Beijing Capital International Airport in Beijing, October 8, 2006. Abe will have a meeting with Chinese President Hu Jintao in Beijing on Sunday and fly to Seoul for talks with South Korea's President Roh Moo-hyun on Monday. [Xinhua]

"But I wasn't able to go through with it mentally and I didn't have the confidence to raise a child, so it didn't become a reality.

"I am telling myself that it must be my fate to contribute to society in some way other than rearing children," she said.

Akie Abe voiced sympathy for Crown Princess Masako, who has a 4-year-old daughter, Princess Aiko, but has been under intense pressure to bear a male heir to the throne.

"I think the crown princess had an unimaginably hard time due to the strong pressure, which is incomparable to us. But I guess Princess Aiko was a relief to her," she said.

Princess Kiko, the wife of the emperor's second son, Prince Akishino, delivered a boy last month, Prince Hisahito, giving the royal family an heir and ending for now a debate on allowing female succession a proposal opposed by Shinzo Abe.