The magazine’s owner, Emap, said the move would enable it to "reinvent the title" in order to "build the magazine’s growing sales momentum".
A spokeswoman for Emap said: "First will return to the news- stand with a weekly frequency in September as a key member of the UK’s most modern and exciting women’s weeklies portfolio, alongside Emap stablemates Closer, Grazia and More."
Earlier this month, Emap announced Ennis’s appointment. She takes over the editorship of First from Jane Johnson, who left last month to join the News of the World as deputy editor.
First launched in May 2006 and was billed as a weekly for women less interested in celebrity gossip and real-life stories, but more interested in current affairs.
In its first set of ABCs, covering the second half of 2006, it achieved a circulation of 100,439. Its launch target was to sell 150,000 copies by May 2007, but it is believed to have failed to reach it.
Separately, Emap announced it is putting millions of pounds into repositioning FHM to appeal to an older, more sophisticated audience and its More magazine is moving from a fortnightly publication to a weekly from September.
First
First goes fortnightly prior to relaunch
LONDON - Celebrity and current affairs magazine First is to change its frequency from weekly to fortnightly as it prepares to relaunch the title under new editor Jane Ennis.