The wartime paper restrictions and rationing caused most of the big comic book publishers to cut down the page size of their bigger books, cut down the number of titles they published, cut down the frequency of issuing given series, to condense from 3 horizontal tiers to 4, and from 2 vertical to 3, and to "buy" unused paper allotment from publishers of any genre, or even other types of magazines and even hardbound books, as was done by ACG, Better/Nedor, Lev Gleason, Jerry Iger, Bernard Bailey, having prestige hardbound book publishers like Cambridge House, La Salle Publishing, Wm. H. Wise, Rural Home Assoc., and other never before and never again comic book publishers "publish" comic books under their names (when the comic book publishers listed above. For that reason, I am sure that Sheena (like a lot of other publishers monthlies or bi-monthlies were changed to bi-monthlies and quarterlies, respectively, to keep the series from shutting down all the way until the end of The War.
Link to the book:
Sheena, Queen of the Jungle 04