This is what we found on Wikipedia regarding the Laura Misch:

The following women have appeared in the American or international edition of Playboy magazine as Playmate of the Month. Those who were also named Playmate of the Year are highlighted in green.

A common misconception is that Marilyn Monroe was a Playmate of the Month. She appeared in the first issue of Playboy as the "Sweetheart of the Month". The term "Playmate" was introduced in the second issue, but that term was applied to Monroe in several later issues.